The difference is the ability for new firms to compete.

With centralized planning, there's only one source. If that source is inefficient or corrupt, that inefficiency and corruption stays around. You can try to regulate, threaten, and police it, but nothing can really take it down.

By contrast, Walmart and Amazon might be very large, but they still have competition. Heck, Amazon started less than 25 years ago. Remember when Walmart was going to be the future of retail? Well, now people say it's Amazon. So, it's one generation for the crown to be passed? Apple was in such dire straits that Michael Dell thought they should close up shop and return cash to shareholders. Now look at Apple. Yahoo had the chance to buy both Google and Facebook. Heck, it wasn't really until the 90s that Walmart became what it is today: Sears and Kmart were the big stores.

The point is that, while companies might have large barriers to entry, competition sneaks in. Walmart looked like no one could compete with it. Today, I wouldn't say it's precarious, but it certainly doesn't look unstoppable. Sears was huge and today people make jokes about it.

Companies like Amazon and Walmart create barriers to entry by building up capital. It certainly does stop some competitors, but I don't think we've seen companies able to hold on for long.

It's also not necessarily about whether the company turns a profit. Government-owned, centrally-planned companies don't turn a profit, but they might be run incredibly inefficiently. It's not just Amazon's low-profit range, but it's efficiency that keeps it where it is. Plenty of companies are being run right now with low to negative profits, but also not being run super efficiently.

How many companies have been "the unstoppable juggernaut" for 50+ years? Can we name a few? AT&T isn't the AT&T from 30 years ago. Remember when AT&T had wireless and home TV and broadband and long distance was king? Well, that company thought long distance was the future, spun off its wireless division and sold AT&T broadband. SBC eventually bought what was left of AT&T on the cheap and renamed itself. Microsoft was the unstoppable juggernaut... and then Apple and Google came along. Walmart was that in the 90s and then Amazon came along, people started using other stores, etc. Heck, Verizon and AT&T seemed like no one could compete with them and then T-Mobile comes along and kicks of an era of amazing growth for them. That's an industry that relies on a limited amount of wireless spectrum that's insanely hard to compete in and T-Mobile started grabbing all the industry growth and forcing the big two to lower their prices and offer unlimited. American automotive companies were once kings and while they still exist, they're a lot smaller and have lost that powerful position. Office supply companies were big and everywhere and OfficeMax and OfficeDepot combined to survive and Staples doesn't seem to be anything powerful. I mean, Staples was started in the mid 80s and had a nice upward trajectory and seem to be on a graceful down-slope. Heck, Blockbuster Video. Talk about a staple of American life. Despite stores everywhere, huge brand awareness, etc. they got toppled by Netflix. Oh, Nokia! They were huge and worth nearly 6x what they're worth today a decade ago. They saw the iPhone and just stalled out. They saw Android and stalled. Finally, Windows Mobile, but it was too late/the wrong OS.

There are certain natural monopoly industries like utilities, but even in the cable TV/internet industry, they're looking less secure for the long run. Many people are cord-cutters for TV, opting for Netflix and other internet-delivered video. Many people watch on tablets which might use 4G rather than WiFi and that's likely to accelerate over the next decade as wireless networks get much faster with much more bandwidth. Tesla seems like it might want to compete with utilities over the long run with a combination of solar roofs and home battery packs.

Amazon is certainly powerful, but so was Walmart as Walmart scurries to stay in the game. It's hard to come up with companies that have really been that juggernaut for long. Walmart was a relatively new entrant against entrenched retailers like Sears. Amazon was a new entrant against Walmart. It's certainly not easy to unseat a powerful company, but it also seems difficult to stay at the top. Whether it's inefficiency, inability to pivot to new ways of doing things, or just markets that dry up as they're replaced by something else, companies have a hard time staying in such powerful positions in our society for long.

And that's the difference between a market with powerful companies and central planning. Central planning would have said that Netflix isn't a worthwhile attempt. We already have all these stores, what will we do with the employees, isn't it a waste to shutter so much investment and capital we've built up in the old way of doing things, the new model doesn't look as good economically (yet), etc. In fact, that's basically what companies do. Shipping DVDs? Ridiculous. You're maybe paying $1 for the round-trip on the DVD (including labor) and charging $10/mo for two out at a time? Seems like it would never work. Shipping books? People want to browse at their bookstore, people want goods immediately, and shipping eats into profits. Ridiculous! Better search? Nah, people want portal sites and Yahoo is the biggest! The iPhone? It doesn't even have a keyboard which is an essential part of devices like Windows Mobile. Wireless and cable? We think the future of AT&T is our long distance service which currently has better margins and lower investment cost than that newer technology.

When you have so much invested in one way of doing something, it can be hard to pivot as the world changes. You become hesitant to kill your cash cows and might not try new things aggressively. In a centrally planned economy, no one challenges that. In a market economy, companies come along and do challenge that. Even when offered their competitor, they often shrug them off! Blockbuster was offered Netflix for $50M. It wasn't profitable at the time and seemed niche - PASS. Yahoo was offered both Google and Facebook and thought the prices were too high. Apple announced its iPhone 6-months in advance and most competitors just thought it was dumb. Luckily, people can pursue these endeavors outside of one, centrally planned company.