It will be great this set up can be commoditised so everyone can buy one for themselves/family.
The reality is that if you go to any family BBQ and start going on about the importance of self-hosting, I - someone that’s been working with computers my whole life - am going to roll my eyes and not be all that interested in the conversation, let alone anyone else there (chances are they don’t want to talk about computers at all).
The reality is that these open-source / self-hosted solutions are, the vast majority of the time, harder to use and maintain. There are few things that sound less appealing to me than dealing with the realities of helping my family and friends with using any of that stuff.
This is all just some nerd’s out of touch pipe dream.
Yes, though only because it's a lot of trouble to set up today.
If it were completely commoditizated -- imagine one more button when setting up a new phone ("Choose where your data resides: Apple, Google, Facebook, Self hosted") and it was completely transparent then it would be used much more, especially if that's complemented by one of the nerds setting up e.g. a neighborhood sync server and everybody around knowing it and using it.
So yes, you are not wrong but the situation can change dramatically if ergonomics are improved. Which sadly most of the nerds never work on.
As for waiting, yeah, sad story, but most of us don't want to be on the computer for 16-18h a day anymore. I implore any of the more privileged programmers -- people with job security, $200K+ annual salary, a lot of social safety nets -- to open their eyes and stop fucking around with the one millionth LISP interpreter and just start making non-corporate-controlled tech already.
In other words, if you built one nice Golang / Rust program and only update the server once every 3 months, you can go quite far without touching it too much. Likely 3-5 years.
I will agree that nerds work far too much on pointless pursuits.
I've had great luck convincing even church ladies in their 60s to use both just by explaining that "end-to-end encryption" means that only the sender and recipient can read the messages, not big tech companies and advertisers.