Mastodon has been usable, and simple, as well.
I signed up for my tildeverse account once they spun up an instance, and I followed people I saw posting. And now, I’ve collected a fair number of followers and people I follow to see what they say.
Works quite well.
So, what isn’t usable or simple?
We have Android and ChromeOS for those “just want an appliance” users.
The rest of the distros are for those with varying needs. Arch, Gentoo, for the full control folk. Debian for stability folk. Ubuntu for cloud. ELs for data centers.
Etc etc etc