I’d think that large countries and groups of countries (e.g. USA, the EU) could implement their own mega marketplaces, leaching off much less money

Exactly! I've been saying this for a while that certain market places like amazon and ebay should become more public utility. I think craig's list is the rare example of something actually owned by a person that is not just optimizing for profit. Social media should similarly be federated, which now with e.g. lemmy and mastodon seems much more plausible.

Another example is that the recent payment service directive has finally created instant wire transfers - e.g. I can wire money instantly to a shop without having to wait a few days or needing a payment processor. It's insane that it took 30 years for instant payments. So maybe the 1.5% to 3% tax that paypal sucks out of ecommerce economy can finally end.

So maybe marketplaces could be federated as well and supported by regulations. For example some kind of open standard to exchange price info and order conditions etc. so that different services can use the same network of vendors and the customer can easily move from amazon or ebay to other alternatives without loosing the market network.

So if there is techno-feudalism it definitely can be dismantled politically. Thanks for your comment, and thanks to Varoufakis - this is actually a very valuable insight I believe. I remember like 10 years ago people started talking about the monopolies rising out of the internet and how they should be broken up. But it was clear to me that classic anti-trust measures wouldn't work, because there are network effects that are incredibly valuable. You don't want to split up facebook because 10 separate social media are much less useful. But maybe now we're at a point where we have the arguments (techno-feudalism) and the solutions (federation and regulations like a protocol like activitypub) to suggest actual policy! 🙂