Say this to a non developer. This just isn't realistic for the majority of people, nor do they care, or should they. What we need is interoperability between services so that backups and transfers are much easier. That isn't the case just yet. If we moved to a more API first world then it would be very much possible. With the advent of GPT related stuff it's clear we're going that direction and the interface for everything is changing too. So the concept of what is your website might fundamentally change too.
Well, there used to be FTP for this (esp. with a GUI client): just move your files from one window to another, no APIs required. Or, if this was still too technical (or too little), you could setup a folder for sync.
I don't think that it's obvious that that will ever be the case. Service providers have poor incentives to make your content movable, much less your following.
