I wish people understood "you can just set up your own server!" is not a good answer to people with instance issues.
It's true *in theory*.
If you have the money to pay for a server to run it on. 5 USD a month may not be a lot to *you* but it's out of some people's price range.
If you have the technical knowledge to set up and admin something like Mastodon. Not everyone does, and not everyone who lacks it has the time and resources to learn.
That's why stable, well run instances matter.