Does It Really Matter How Much Switch Sells?

[Peh]

You need to build a certain userbase on your system for several publishers to develop for. The higher the userbase the more likely the game is being bought. That's kinda obvious.
Nintendo failed to deliver that with the WII U.
But that's not the only criteria. You system has to be also compatible with certain standards like game engine i.e. UE4. Make it easy for your developers to make games for your platform.