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If you think we're centralized and you're "downvoting to disagree" at least have some decency to explain how we're centralized. There is nothing that Amazon sells that I can't buy an alternative product at a dozen other retailers for comparable prices, for example.
Due to network effects, there often aren't good alternatives for social media like Facebook or collaborative cloud tools like Google docs.
For games, it's not unusual for indy games to only release on Steam. Even when there is a physical release, that option is becoming increasingly difficult (e.g. many computers no longer have a built in disc drive, many stores no longer carry PC games, etc.).
This is less common than the previous two examples, but it may be difficult to find niche products outside of Etsy. For example, I haven't been able to find another place to purchase this specialized martial arts equipment: https://www.etsy.com/listing/175827423/
So Steam and Etsy themselves trend toward some amount of centralization, but in the case of Stream for example you have Playstation, Microsoft's platform, Stadia (soon to be cancelled I'm sure), Switch, Epic game store, iOS, and others. They aren't all exactly 1-1 comparable but I think that's ok. Frankly, you can get games from a lot of sources. You might say you can't get an indy title from one of these sources that you can on Steam, but you can't buy Halo on Playstation either - that doesn't make things centralized. It's a very competitive market.
In the case of Etsy I think you're a little more right, but there's no reason that has to continue to be that way.
Steam and Etsy are actually two companies that, if I were unable to use them starting tomorrow, that would basically have zero impact on my life.
Whereas, although I do order from a variety of online retailers, going cold turkey on Amazon would be a fairly significant inconvenience for me--although some seem not to use them much.
But what about your gmail? You'll lose all access to your email
The antitrust laws prohibit conduct by a single firm that unreasonably restrains competition by creating or maintaining monopoly power. Most Section 2 claims involve the conduct of a firm with a leading market position, although Section 2 of the Sherman Act also bans attempts to monopolize and conspiracies to monopolize. As a first step, courts ask if the firm has "monopoly power" in any market. This requires in-depth study of the products sold by the leading firm, and any alternative products consumers may turn to if the firm attempted to raise prices. Then courts ask if that leading position was gained or maintained through improper conduct—that is, something other than merely having a better product, superior management or historic accident. Here courts evaluate the anticompetitive effects of the conduct and its procompetitive justifications.
"Market Power"
Courts do not require a literal monopoly before applying rules for single firm conduct; that term is used as shorthand for a firm with significant and durable market power — that is, the long term ability to raise price or exclude competitors. That is how that term is used here: a "monopolist" is a firm with significant and durable market power.
https://www.ftc.gov/tips-advice/competition-guidance/guide-a...
What you may think has little relation to governing regulatory law.