>they silently declare war on existing tenants by demolishing their homes while they live in them

you said, "That's nonsense”. Sadly, I’m afraid it isn’t.
Here are some articles that might show you as much:

https://ny.curbed.com/2017/11/17/16670180/rent-regulation-la...
http://www.nydailynews.com/new-york/nyc-crime/bklyn-slumlord...
https://ny.curbed.com/2017/8/31/16233332/office-of-tenant-ad...
https://www.dnainfo.com/new-york/20120506/chelsea/chelsea-ho...
https://www.amny.com/news/tenant-harassment-brooklyn-1.14746...
http://www.nydailynews.com/new-york/brooklyn/landlords-haras...
https://patch.com/new-york/bed-stuy/landlord-fakes-burglary-...
https://www.nytimes.com/2016/07/27/nyregion/new-york-landlor...

I think 8 articles demonstrates my point, but there are dozens of others.

Thank you, though, that helps me understand. I want engineers and others who think of moving to NYC to at least be prepped for reality, because I was not. While our situation isn’t as bad as the horrifying homelessness in tech cities in California, it is a close second, with problems that date back before the tech boom, and growing homelessness that will sadly soon rival the problems on the west coast. We were speaking about Airbnb in relation to this situation, and I see it as a force that could bring about real legal change through the process of legal sparring that might benefit tenants. It has that power because it threatens the current power. Tenants can’t do that- only huge financial giants can, if they work with tenants. Landlords have a powerful lobby here. The tech boom in NYC is only one of many new pressures on an already failing housing system here. The very long history of landlord tenant relations in NYC can seem like operatic exaggeration to someone who has not lived here as a renter who is doing well but isn't uber-wealthy. I can tell you that the declaration of war from a LL to a tenant is just as often not silent. It isn't subtle, and threatens life and safety. I lived in a rent stabilized building during the upscaling of what used to be a regular, family-oriented residential area of of Brooklyn. That area and many others in Brooklyn became ultra-luxe-hip and glittering faster than I've seen any previous gentrification move here. (Bed-Stuy happened very very quickly but not as fast as my previous neighborhood). And it can't rightly be called "gentrification", because unlike Bed_stuy, the area was too much of a well-maintained destination to begin with. Some of these landlords (mine included) held rent-stabilized properties in this area. When serious repairs were needed over the years, the LL would ignore calls, forcing residents into housing court to get emergency repairs done. In fact, this is often the only method stabilized tenants have of getting relief of any kind in NYC. The first time a tenant does it, they think, "Boy, i must have found a rare, totally insane landlord!” At housing court, they see how many others are dealing with this, and then they talk to friends who have lived in NYC a long time, and begin to read articles on the topic, and eventually realize it isn't all that rare.

These are not slums, mind you, just rent-stabilized buildings- they aren't all ugly on the outside. Many tenants were paying $1500/mo for tiny apartments 7 years ago, so not cheap by any means. The tenants were advanced-degree-bedecked professional architects, lawyers, professors and journalists, and they worked for legit companies like Spotify, Associated Press, NYU, Columbia, Google(gasp!) etc... I lived in such a stabilized building that was sold to a new owner who decided to “renovate” so they could charge “market”. (to give you an idea, the rents went from $1300-$1590 under stabilization to $2500-$4500 when they were done, and these were tiny apartments, the largest of which was a small one bedroom) The tenants were told that the LL was making repairs and that these repairs would last for a month. Well, the process lasted three years until it was shut down by the city after homeowners in the area complained about illegal construction. Eventually, the new owners finished.

Some tenants (who were able) moved out, some of us who could not (due to job responsibilities) stayed, thinking that it would be over soon. Those who stayed were not offered buyouts- they were always told it would only last just another week. Instead, they were subjected to constant water shut-offs, sledgehammers in the apartment above, below and on either side beginning at 6 am, lasting all day and long past the legal time to be doing construction. Dust mitigation laws were not followed and the place was filled with toxic dust and hanging pieces of plastic. Debris was everywhere. At one point and for a couple months, the unit next to mine was missing 3 of its 4 walls, just open to the 4th floor outside air- an open floor that a helicopter could land on. Ceilings fell in on existing tenants, one getting nearly hit on the head with falling brick from a ceiling that opened up while she sat on her toilet. One came home to a wet ceiling that had fallen onto their bed and destroyed it. Holes in floors and walls from the demolition. One was hospitalized with acute bronchial inflammation for several months and another developed a skin rash and repeated eye infections. One slipped on the stair and broke their leg. Finally, the tenants banded together and asked for buyouts after several months of this. There were not enough tenants to collectively hire adequate legal help. The landlord said he was ready for “war” with us. (the entity with billions behind it is the powerful one, and the tenants stand no chance) Eventually, the few remaining tenants got very small “buyouts" (a few thousand and a forgiveness of the rest of the months left in their lease, because...we were still being asked to pay rent!- without heat, without any water, and all of the above)
When you go through something like this, you think it’s a crazy exception. In NYC, it has become an epidemic.

And now, the end result of years of this kind of slumlord-in-training gives us many newly minted and experienced market-rate landlords who know exactly what kind of abuse and neglect they can get away with because of the lack of enforcement of the rights of a tenant in the courts. (rights meaning basics, by law: a certificate of occupancy filed, inspections made, an onsite super to handle emergencies, no discrimination, heat, hot water, keys to the apartment, a legal lease, no using of security deposits for personal finance, no unannounced entrance into apartments, no fireworks or crazy parties until 5am during the week, and to get amenities you pay for like parking, a working laundry, a gym, trash removal) I think at $2000+ a month, a tenant should not have to take a LL to court to get a key or to stop a gushing leak. What is driving this? I think LLs who were previously slumlords have now entered the market rate arena. But I think they don’t have the cash flow to hang with the market. In my current, new, market-rate apartment in gentrifying Brooklyn, here are some things the tenants have had to deal with: renters were promised parking spots but no renter is allowed to use the parking lot and it sits completely empty, the certificate of occupancy was not filed and tenants needed to do a collective rent withholding to get him to do it (if this CofO isn’t filed, the city can chain your building and prevent you from entering-- yes with all your stuff in your apartment, including your computer-- for as long as they like until the LL files it- can go on for years, and yes, this happens, traditionally in Soho, but now in Brooklyn), the laundry room often has no working machines, many tenants don’t now have e-keys that would let them into their buildings because they are cheap and have broken but the landlord won’t replace them, recalled fire alarms, ridiculous electric bills of $500+ a month, gushing leaks that go unfixed, mold in common areas due to shoddy plumbing, armed homeless men sleeping in gym all day, parties on roof and in courtyard thrown by and attended by non-residents until 5 am with fireworks... and on and on. And I have friends who report the same in market-rate buildings. Is a six month security deposit and $2000 a month in rent enough to expect basic services? Apparently not in Brooklyn right now. I think this wave of market-rate tenant harassment is new, and word of it will spread eventually. But there have to be a lot of individuals speaking up, like here, on HN and within their communities. People don't like to talk about it. But eventually, with enough people reporting, it will be believed--it might take a while, and that is too bad. I’m glad Airbnb is ready for a fight.