> You don’t know what demand means in an economic context here. Ops point is that as wages increase, people aren’t going to accept 70 hour workweeks if they can get by on 40.

Which misses the point that when these changes started being demanded and won people couldn't afford to walk away.

> Feel free to point them out and show how unions were required in every country to get the same thing.

Nice try, but that was not the claim I made, nor one I even agree with. The 8 hour working day was largely won by US unions, after which it became substantially easier to win elsewhere as the doom and gloom predicted by employers didn't materialise and reduced the perceived need to resist it.

With respect to US unions, there is plenty of material you can easily google, but you can start by looking at e.g. the 1835 Paterson textile strike, which was one of the first major ones, and which "failed" when employers only offered about half the reduction in working hours employers demanded, but it nevertheless gained them a significant reduction as a direct result of the strike.

> Union members were likely emboldened as pay increased because they could ride out strikes.

History largely shows the opposite. Workers coming to the cities facing lack of employment opportunities were relentlessly exploited, and were a major factor in the growth of labour unions.
In the US you also saw major effects of actual salary drops in some cases, e.g. the Great Railroad Strike of 1877.

Union members risked life and limb and imprisonment early on because the conditions they were working in were horrific. Unions have softened and their membership has cratered as pay then increased because if anything better paid workers are less interested in disrupting what they already have and tend to be less interested in putting effort into it.

> At the same time, people could just get by on fewer shifts because pay increased. This creates downward pressure on required weekly hours (because many people to value their time), regardless of the union activities.

This is just entirely counterfactual. Taking fewer shifts wasn't generally an option on offer, and didn't become an option until decades into the fight to lower working hours.

> (it’s literally union propaganda)

It's literally true, whether you're pro union or not.

See e.g. the Bay View Massacre, when the Wisconsin National Guard fired at strikers demanding an 8 hour working day and 7 people died as a result. It is by no means the only incidence of US government or Pinkerton agents and others firing directly at strikers.

The reason May 1st is the international day for labour demonstrations are incidentally a direct after-effect of the Chicago Haymarket Massacre, also an outcome of the eight hour working day demonstrations. I gave the Bay View Massacre because it's a simpler one - not nearly as murky. Preceding the Haymarket massacre police murdered workers the day before. During the demonstrations at Haymarket, someone - who is unknown - threw a bomb, and so while the police ended up killing multiple murders, it's unclear how to assign blame. Several union organizers were then executed without any evidence they had anything to do with the bomb.

> But consider that many professions flourished without unions (tech, law, banks, engineering, etc).
>
> They are by no means requisite for improvements.

Yes, in roles that are either highly regulated and/or high skilled so there is a reasonable balance of supply and demand people can do well, yes. Nobody has claimed no improvement can happen without them, nor that there are no groups who won't do well without them, so that is irrelevant to the claims I've made.