@rysiek well, look at that! That is a sign of maturity, and I'll guess that OStatus didn't have this when the mentioned fragmentation happened?
There are no guarantees ever that one instance/brand won't get big enough to break away from the ecosystem and manage on their own, to everyone's detriment probably.
Still, it's an interesting discussion. I don't really know enough about the alternatives to Mastodon-The-Software. Some questions popped up:
@rysiek I've migrated my account from one Mastodon instance to another. Could I also migrate to another type of instance if I wanted? For example, migrate my account from a Mastodon instance to another instance running GNU Social?
Could a site admin migrate their entire site, including users and content, to another software? Eg from Mastodon to Friendica or GNU Social?