Let me interject for a moment because I have something to add to this conversation. I've created a number of fediverse platforms and services over the years. Some which you may have heard of, and many you haven't. First this "uniform space" concept. In my universe on the outskirts of the fediverse we've had cross-instance single sign-on literally for years (since 2010). If you click a link to another site in our family tree, you're "magically" authenticated and the site can let you follow people and interact on it and view stuff on that site which was shared to you personally. It truly is one unified space made up of lots of instances. If you visit a remote profile in our universe you click it and you're connected. You can post on their "wall" and comment - if they allow it. If they've got private photos visible only to "Bob" and you're "bob", you can see the photos on your site and their site. If you're not Bob, you can't.
The next killer app is "nomadic identity". We've had this in some form since 2012. We let you clone your identity on multiple instances which are kept in sync as you change your settings, interact with other and add friends. All your content and media and files are included. So moving from site to site is easy peasy. You clone yourself onto a new site and you can either keep the old one as backup or drop it.
I won't say that our early efforts were easy to use - they were quite complex and geeky and we used different protocols because the "web standard" protocols weren't up to scratch for doing this stuff. So we were shunned and ignored by the rest of the fediverse. The software I'm building now is dead simple, but the standard protocols still need some work. We're getting there. Now I work almost completely alone and only a few dozen people use my software. It doesn't have a name or brand. You won't even find it in the fediverse trackers because we're opposed to fediverse trackers and the whole popularity contest they create. You'll only hear this stuff mentioned in passing and nobody is really interested in trying it out. So I'm not here to push my software. I gave up on that long ago.
I'm here to push my ideas. All of this is possible and we've been doing it and improving it for over a decade now. If this is the fediverse you want, make it happen. I did. Don't let anything or anybody stop you. Especially some talking head that says it cant be done or "it's too hard". We're sending messages around the world instantly using engineered sand fercrysakes.
Sorry for not keeping this to 140 or 280 characters. I don't believe in artificial limitations.