I think the Switch can survive without these heavy hitters, Nintendo consoles are bought for Nintendo games, I'm sure we're all tired of hearing that but the more 3rd party stuff they can snag, the better. It should help prevent the drought that the Wii U had.
Still, it feels like to me that whoever owns a Switch will probably also have an XB1/PS4/Gaming PC, where as a lot of people can do with just a PS4, XB1 or PC...if that sentence even made sense. Having just a Switch feels like you're missing out on a lot more games rather than having just a PS4, XB1 or PC.
As for the question in the pole, it's the hardware. It is weak, there is no getting around it. It's a phenomenal handheld but a lack luster home console and unless it sells unpar with the PS4 for years to come (which seems likely based on the first few months), I don't think many 3rd party devs will go out of their way to support it, other than exclusive partnerships with nintendo such as the mario+rabbids game, which could set the precedent for more of these types of deals if it sells well.
"Trick shot? The trick is NOT to get shot." - Lucian
