They already tried it. It's called Threads. It exists. People use it. And other instances have the choice to simply not federate with them.
To me (as unpopular as this sounds) that's the beautiful thing about FOSS and about Federation in particular. No one is stopping anyone from creating their own instance. Even Corporations.
It's the ultimate expression of "Anyone can do what they want, say what they want, believe what they want...but no one else is in any way obligated to listen to them/federate with them"
I know of companies that host small mastodon instances for their staff to communicate back and forth. I know of similar setups with lemmy instances. Anyone can use the technology for anything they wish to.