My thoughts exactly.Realistically, assuming that Sega keeps making the same mistakes due to severe problems with their bureaucratic way of handling things (i.e. communication mishaps, rushing to meet release dates, sacrificing quality, etc.) I don't see them lasting more than 15 years, and that's being optimistic. I do think that Sonic carries enough weight to possibly be handed off to another company of Sega's choosing should they go under. I even think that some of these other companies might do a better job, if they're under a different business structure.
However, that's all based on if Sega keeps making dumb mistakes. On the other hand, if they manage to climb back out of this hole they've dug themselves into, then I could see their products increasing in quality, their names slowly rising in popularity, and the resulting funds being used to create even more quality products. However, that will only happen if Sega faces some major and decisive reformation in the core of their infrastructure. Cutting off branches is one thing, but the higher-ups in SoJ have to change too.