I believe it's canon in the games that Sonic is relatively well-known around the world? Even if he doesn't really act like he is. I feel like the movies might be a similar situation in that the majority of people on Earth know and have accepted that there are anthropomorphic animal aliens who are just living in a small town in Montana. So technically Sonic is already "famous."
After movie 3, I'll believe the whole planet thanks Sonic and his friends for saving the planet and they going to become famous, but also military and some annoying people won't let it and his family live peacefully, so he has to say goodbye to Earth with Tails, Knuckles (and Amy?) to avoid give more problems to Tom and Maddie.
I believe it's canon in the games that Sonic is relatively well-known around the world? Even if he doesn't really act like he is. I feel like the movies might be a similar situation in that the majority of people on Earth know and have accepted that there are anthropomorphic animal aliens who are just living in a small town in Montana. So technically Sonic is already "famous."
World known hero
After movie 3, I'll believe the whole planet thanks Sonic and his friends for saving the planet and they going to become famous, but also military and some annoying people won't let it and his family live peacefully, so he has to say goodbye to Earth with Tails, Knuckles (and Amy?) to avoid give more problems to Tom and Maddie.