This “anyone is free to join any instance, you can just avoid what you don’t like” kind of thinking is perfectly reasonable in theory, but I think what OP wants to know is if this also holds up in practice. You could “defederate” Google and Microsoft by blocking emails from Gmail and Outlook addresses, but the reality is that the majority of people you will need to contact use those addresses. In most cases, your school/workplace will even make you use them for your organizational email. Yes, it is possible to avoid these companies and choose alternatives, but you’ll be isolating yourself from the majority of the network.
The question is not if it will be possible to use the future corporate-owned Fediverse without Meta (of course it will), but if it will be feasible for the majority of users.
Sorry, I don’t get this argument. Is not being able to avoid corporations justified because people are forced to use email? Social media is also becoming a lot less optional these days. I know a lot of small businesses that only share location and contact information on Facebook or Instagram, because they don’t want to invest in building their own website.
I also hate this concept that there is a hierarchy of users in the Fediverse, the “core users” and I suppose, the “idiots who migrated over from a bigger social media site”. Look how well Lemmy performed from 2019 to mid-2023 with only “core users”, it was a graveyard. As long as a real person has an account on the Fediverse that they actively use, they are a Fediverse user, and they must be considered when discussing the Fediverse in general.
There will always be instances that do not federate with corporate instances, just like how you can set up an email server that blocks Gmail and Outlook. But I don’t want to see a Fediverse where these instances are dead and marginalized because corporate instances consumed most of the Fediverse.