> How did we end up with this mess of disjoint chat systems each with their own userbase? Doesn't it indicate that this market desperately needs regulation?

Why do you assume that the regulation that would actually get passed by the actual government would result in effective chat interchange between different protocols, and not just entrench some existing platform while making it technically illegal for another organization to try to compete with them?

> Either you provide message interchange with any other message system operating in a specific country or you can't advertise or sell anything in this country (also app stores must country wide ban).

Would this make it technically illegal for me to use F-Droid to install an open-source implementation of a novel chat protocol that doesn't support interchange with existing chat platforms yet? Does this make it possible for me to force existing chat platforms to be suddenly illegal by releasing a novel open-source chat protocol without coordinating it with those platforms?

> Would email look the same if it was left to be invented by the corporations?

Probably not, but email is a heavily-flawed protocol, so I'm not sure that's a good thing. Also, although email was invented in the 1970s, making it one of the oldest internet protocols still used, it's been extended over the years, and I'm sure at least some of those extensions were developed by various for-profit companies (perhaps ones which no longer exist).