Horsepower isn't everything, usually cost and power consumption come first in SoC selection followed by feature set(of which your GPU is one part of a larger picture).

If you want to really succeed in the SoC space(which is where Arm has) then what you need is volume and I don't think Tegra ever really made any serious inroads there.

The switch is a game console and so it sits somewhat outside of the traditional high-volume SoC market.