Anyone can start their own Mastodon server (or other type of Fediverse server) and there's a thing called "managed hosting" that lets even non-technical people start their own too.
Here's a guide which answers lots of questions about the concept:
➡️ https://fedi.tips/who-gets-to-start-their-own-server
Here's a step-by-step tutorial from Fedi.Tips's sister site which goes through the entire process of creating a Mastodon server through managed hosting:
➡️ https://growyourown.services/making-your-own-mastodon-server-in-10-steps
2
@FediTips You misspelled the Mastodon hashtag. :)