I think this needs to exist, but as a community supported system, not as a commercial product.
Pick a set of open technologies - but not the best, lightest weight, just pick something open.
Come up with a security architecture that’s reasonably safe and only adds a moderate amount of extra annoyance, and build out a really generic “self-hosted web hosting and VM company-like thingy” system people can rally around.
Biggest threat to this, I think, is that this isn’t the 90s and early 2000s any longer, and for a big project like this, most of the oxygen has been sucked out already by free commercial offerings like Facebook. The technical family friend offering to self-host email or forums or chat no longer gets gratitude and love, they get “why not Facebook?”
So… small group effort, resistant to bad actors joining the project to kill it, producing a good design with reasonably safe security architecture, that people can install step by step, and have fun using while they build and learn it.