Are you implying that defederation is a myth? Since the flow of data between instances is conditional on the instances. they are relevant.

I think it has positives. and the negatives can be adressed with new features like a federated identity . something that could allow you to keep accounts on multiple servers combining subscriptions deduping content and letting you control what user to use to interact.

It might be completely false but i read that there were many tankies on other instances. One thing that got in the way of competitors in the past was the high number of extreme right wing people. My take is that people would rather not associate with either.