Why? Pokémon Switch won't make anywhere near the money Pokémon Go made. They made more money the launch year of Pokémon Go then all previous years combined. The console games do absolutely nothing compared to the mobile game.
I don't think they're that far apart, depending on how you look at it. Pokemon Go had $1.2B in revenue in it's first year (and given how huge it was it's hard to see it not declining from that in the future). But Nintendo only get about 19% of that, so around $228M. Meanwhile mainline Pokemon games typically sell a minimum of 15m (although you could add another 7m or so if you include the cash grab 3rd versions), after taking out the retailer cut lets say they sell at around $25 per copy that would be $375M for the original games or $550M including the 3rd version. Sure, that's over a 4 or 5 year split rather than a single year and it does fail to take into account the Nintendo/GameFreak split of the money (we also don't know whether the 19% Nintendo gets from Pokemon Go is the full amount or whether there's also some going to GameFreak.
So in regards to money actually going to the companies that own Pokemon, yes Go definitely would bring in more, but it's not as if the games are "absolutely nothing", they certainly bring in a decent amount of cash too.
Edit: Sources for the Go figures: