How important are first party games to a console?

[DonFerrari]

Wman1996 said:
They are quite important.

For Nintendo, they are do or die. Even Nintendo platforms with large third-party support (either by numbers or quality), still are moved mostly by first-party games. The NES/Famicom could still have the third-party library it has, but without Super Mario Bros., The Legend of Zelda, and Duck Hunt it wouldn't go far.
They helped Sega a lot as well. Now I get that Sega's only sure-fire hardware hit was the Mega Drive/Genesis, but Sega's games attributed a lot to that platform's success.
Microsoft is interesting. Halo: Combat Evolved single handled kept the Xbox console from failing. I say that because the hardware sales of the Xbox were nothing to celebrate. But Halo, Halo 2, and Xbox Live ensured that a future Xbox was possible. Xbox 360 thrived with first-party games, but a lot with third-parties as well. And the Xbox One has very few true exclusives. And the first-party games it has aren't very acclaimed.
Sony seems to be the only one who can coast by without massive first-party support. Don't get me wrong, first-party games have helped make PlayStation what it is. But it wasn't Gran Turismo (though this game helped), Spyro, or Ape Escape that turned the tide to make the PS1 a titan. It was Final Fantasy VII. And it was GTA (a timed third-party exclusive) that helped contribute to the massive success of the PS2. PS1 and PS2 had massive amounts of exclusives that weren't first-party. With PS3 and PS4, that has changed due to increased competition from Nintendo and Microsoft, as well as PC.

Xbox sales may not have been massive, but for their first system and outselling GC with a great help from Halo is really something.