as much as it rages me out,i luv it.
Nah, because Microsoft paid quite the amount of cash to the devs to have it as a "Xbox-only" title in the console market (note the console market part, because that's why we also have it on PC).
Besides, considering the requirements on PC, I'd say that, just like many of the games that are designed for the PC/PS4/XB1 nowadays, they would have to change a lot of things to make it fit. Even with fine tuning, there's no assurance that, in some boss battles, the game would be smooth even on the Switch, which have barely 25% of the PS4/XB1 processing power, so, think about the 3DS, which have ~25% of the Switch's processing power if it's a New 3DS, and it's running at normal CPU frequency (268MHz mode, the 804MHz mode would put it a bit higher, but not that much. Also, the 3DS "GPU" is super obnoxious as I read, and doesn't support much in terms of graphical APIs). If we're speaking about vanilla 3DS, you can cut the power down by 50% more (two less cores + lack of CPU cache)
Which mean that in the end, you'd be trying to run Cuphead on a system that have:
Switch: ~25% of the power of the system Cuphead was "primarily" designed for (excluding PC because, PC is flexible, so it's harder to measure properly)
New 3DS: ~6.25% if in Normal Mode, ~12.5% if in Overclock + Cache mode
Old 3DS: ~3.125% (Old 3DS doesn't have a 804MHz mode or a CPU cache)
So, yup, sorry to be that guy who ruins parties, but, running Cuphead on a 3DS would be hard, very hard.