Now you lost me. Expecting one server per person in a household is unrealistic. Even if software becomes perfect, what about the hardware aspect? Expecting a family of 5 to have 5 servers all available and reachable from anywhere sounds like a nightmare, and just a waste of electricity.
Your whole premise is that self hosting software can become a one-click deploy, if they can achieve that I'm sure different settings per user is possible. If who is legally responsible about what your brother does with the family serve is really such a big question, then let's just accept widely adoption of self hosting is not going to happen.
A server could be a $30 silent soap-sized box hanging on the router consuming 5 watts, you plug it in and it sets up services and domains ready to access. Why would this be a nightmare? It is already feasible on all levels. Assuming the house has fiber, reliability shouldn't be much of an issue.
“Hello, Metropolitan Police here. We have a warrant to seize… docker container ab38asdf8765jk on your home server. Go ahead and export its attached volumes and the image. We’ll wait.”
A 30 dollars box will replace cloud storage, photo storage, video steaming, and all the other services people expect to have? I don't think you have though through what exactly you're trying to replace, we're not talking about tech people wanting to host their static blog here.
A Raspberry Pi 5 already does all of the examples you mentioned. Add a hard disk o it, and a somewhat-reliable power supply, and you're looking at a hundred bucks. We are not that far away from that.
Does it replicate Netflix? No. But honestly, most people do not host videos on Netflix.
Now add raid storage, nobody should keep their photos and other important documents in a single drive, then at least double the price because you're not going to sell a raspberry kit to the general public but a polished product that needs almost no install steps. Or triple it, because you're also going to need tech support and updates.
And how are you going to reach your personal server? More and more people don't even get to have a public IP for their router anymore, and having every non-tech person punch a hole in their firewall to access their photos... I'm sure that's going to go well.
And if you somehow manage to do that, how are you going to share your photos in your personal server with your friends? Because that's pretty high in people's needs.
if the servers are all in the same house then the police is not going to ask who's server they can take, they are just going to take all of them. so if that is a concern, it would be lost. but GP is not talking about people living together, but not sharing with relatives who live elsewhere.
Your whole premise is that self hosting software can become a one-click deploy, if they can achieve that I'm sure different settings per user is possible. If who is legally responsible about what your brother does with the family serve is really such a big question, then let's just accept widely adoption of self hosting is not going to happen.