The internet overall is a much more mature place, and basic literacy of using online spaces has grown immensely. I don’t think there is a good way to build new platforms that avoid including everyone these days. No more intrinsic filters due to necessary domain knowledge or access to the internet.
Asynchronous spaces will always be like this moving forward. It seems.
In my opinion, synchronous spaces will continue to grow in popularity due to many factors.
Lemmy can still be useful, federated online spaces are still worth sorting out and building.