MS leaving the console race would be good for gamers.

[MyCodenameIsIan]

Don't Microsoft, Nintendo and Sony invest significantly in first party development? Competition drives innovation.

Without competition there would be no drive to push hardware limits and continue to r&d more advanced consoles.
Without Sony we wouldn't be playing games from CD's, which led to DVD and Blu-Ray.
Without Sega we wouldn't have the Dreamcast controller, which evolved into the Xbox controller which in turn Sony took many design cues from for the DS4.
Without Microsoft we wouldn't have Xbox Live, which in turn spawned the Playstation Network.
Without Microsoft we wouldn't have Xbox Live Arcade which paved the way for indies/small scale console development.
Without Nintendo we wouldn't Motion Controls or the Wii, which spawned Kinect & Playstation Move. (OK perhaps we could have done without it)
Without Microsoft we wouldn't have the multi-media features/apps found in the X1 and PS4.
Without Sony we wouldn't have Instant Game Collection which spawned Games With Gold.