I think walled gardens are inevitable, and desirable, and the walls have doors. I think we'll end up with a big mainstream garden/island of federation of U.S. pop culture w/ Threads and CNN and my mom. Other gardens/islands for things like child safe content, adult only content, servers that refuse to federate with for-profit servers (where I'll be), etc.

Also, I suspect it will (or already is) be common for people to have multiple accounts on different servers for different purposes. I find myself blocking all porn, not because I'm anti porn but it's just not what I'm looking for when I log in with this account. When I want porn, I'll make an account on the nsfw server just for that.