I feel like that's what made the Sonic fandom take off like crazy was the almost-complete concept that was just a little bit too simple for everyone in some way, even the ultra-minimalist Sonic fans. I think everyone can agree that back then, before we had internet to help along, no one really knew what the backstory of Sonic was, but anyone interested would sure do their best to figure it out. And with the way video games were in general back then, when a cartoon was made, even more 'fandom'-esque material was created and the rest is history