I agree with owning the network devices, and lack of control here is a problem that still has solutions.

And self-hosting personal services makes sense and we're able to do that.

BUT, we don't own the connections. There's always going to be shared infrastructure for connecting these devices worldwide, and without an ideal state of Communism or utopian capitalism we're not going to own them or want to be responsible for them. Any kind of service that depends on a central database is not going to be communally owned.

Ownership is an economic problem, the technical aspect is merely interesting. Bitcoin might be a great example of this.