It's something I really appreciate about Sega's handling of Sonic IP: as long as you aren't trying to make money you can pretty much get away with anything. I think Sonic's continued popularity is in no small part due to this policy.
I disagree. Sega can be an awful-bully when it comes to their IP. It wasn't until the SteamDB issue went viral that they backed-down [1] and the Streets of Rage remake. [2]
[1] https://arstechnica.com/gaming/2021/03/sega-forces-mistaken-...
[2] https://www.destructoid.com/sega-has-streets-of-rage-remake-...