For this to succeed, I think you'd need a company that provided boxes as a service. Instead of having to order anything and plug it in, you just sign up online, the same as today's social networks.

Here's the twist: the company (presumably a non-profit or social purpose corp) would also offer the ability to buy your box, at which point they mail it to you; when you plug it in, your existing data is copied to it and you begin to self-host instead.

This makes it easy to sign up for and try out, while also offering a path toward self-hosting, once you decide you like it and don't want to keep paying the monthly fee.