I doubt this is like a 3DS situation. The Switch will be treated more like a home console than anything, and Nintendo tends to move on from their home consoles quickly. The 3DS was supported for so long because it didn't really have a direct successor (like the 3DS was to the DS). Once the Switch 2 is out, the original probably won't get new games at all unless its a few smaller third parties still releasing stuff to try to take advantage of the large install base. At best, Nintendo may do a few cross platform releases, ala Breath of the Wild, but those will probably dry up quickly, unlike what happened with the PS5, where cross platform games became its entire library.