Dramatic take: Sega "died" for much less mistakes.
Sega died for much bigger reasons than MS. Sega died due to hardware problems and because they had a really poor vision for the Dreamcast.
1: Sega making the 32x and Mega CD were the first mistakes. Then their American and Japanese divisions were making different hardware. Then the Saturn released, was hard to program for and Sega only really had arcade type games to offer. Then the Dreamcast was released too early.
2:The Dreamcast released as basically an arcade machine, not where the industry was heading at all.
MS should have been building their studios or at least building close relationships with studios with talent since the original Xbox but they didn't. They waited until the end of their 3rd console to start getting serious about their studios, that's crazy. Luckily they have heaps of money so they can ride this wave of no software pretty easily, they just better hope they don't lose fans with this mess..