Sega's [0] main business is pachinko (so gambling). To them Sonic brand being used by fans has very little consequences, if not building most needed goodwill toward their other brands.
That's where Nintendo is fundamentaly different.
That's where Nintendo is fundamentaly different.
Also don’t forget that Sega was “originally an importer of coin-operated arcade games to Japan and manufacturer of slot machines and jukeboxes”
Sega was mostly into normal arcade games, and Sammy baught them for their expertise to improve Sammy's much more profitable gambling machines. It's Sammy's CEO that took the lead, and Sonic and console games became a mere side business.