
The fact that Mario won and Sonic failed is unfortunately not debatable, the numbers speaks for themselves. The big question is why? So, let's look at a few points.

In an interview, SEGA Sound Team lead composer Tomoya Ohtani revealed that Sonic’s global music success didn’t come from chasing trends overseas.
I think this is how Japanese devs need to think. Catering to the west is a terrible idea. I personally, seek out Japanese developed games because they bring a unique experience to gaming. They just stand out more that way.
The sonic music is iconic the mega drive games were some of the best on the system but i wouldn't say they were free of western influence especially since 3 was composed in part by Michael Jackson
But honestly most of the crush 40 soundtrack music lives in my head rent free
Uhhh that's a strange thing for him to say. Even in the interview he admits to listening to a lot of western music.

TNS - A group of passionate Sonic fans has released a full 150-page design document in a bid to help SEGA get Blue Blur's design back on track.

HITMAN Signature Edition lands June 5 on Switch 2 with 100+ hours of content and Mario & Luigi–inspired pre-order bonuses.
Because most Sonic games suck compared to Mario games. I'm not including spin offs, we all know how many crappy ones that featured Mario released.