Let me expound.....
The library of consoles, or genre of arcades did not sink SEGA. SEGA (mainly Japan) sunk themselves. A litany of poor business decisions, spearheaded by stubborn, xenophobic dinosaurs.
No 32X as SoA didn't want it. Support the Genesis longer. Dumping mainline support in 1995 chased many a secondary market buyer to the SNES.
Make the deal to replace the Genesis with the Sony Playstation. Sony of Japan, nearly as backwards as Sega of Japan, had no interest in challenging Nintendo. They would have been quite content with supplying hardware and games to Sega, and forgoing all the risk.
Quite possible Sony never enters the market on their own. Even if they did, SEGA would have been in a tremendous market position, and would have had ample time to prepare the Dreamcast for eventual launch. Meaning, things like ethernet, hard drive, built in rumble controllers, and DVD playback would have been standard as they were the competition.