This means Sony will be the last man standing in the 'console market', while everyone else moves to 'media center with gaming capability market'.

There isn't room for more than 3 main companies on the consoles market (and even 3 is maybe too much...), but you will always have some other companies ready to go if one of the 3 fails (Sega failed, Microsoft arrived...). There isn't a lot of money to make if you fail, but look at the Wii or even the PS4 for now. Playstation is one of the only profitable divisions of Sony.... 

Google, Facebook, Apple, Samsung, maybe Amazon would all benefit from a gaming device (increased software use or increased sales of other devices), I'm sure some of them are thinking about it. The market is full right now, but if Xbox or Nintendo fail...

I actually count PS2 era as exclusive territory. But it won't happen because X1 is more competitive than the OG XBox. I prefer it this way. The PS2 dominance led to the PS3 fat. Without the 360, it would remain an expensive machine and everybody would have to buy it. Last gen competition made them up their game with the PS4.