They've had a couple pretty well-received Pokemon launches in Z-A (not quite mainline, but also about as close as you can get outside of an actual mainline games) and Pokopia (which kind of took everyone by surprise how well-designed it actually was), and don't forget the that the Switch 1 era was sandwiched by two insanely popular Zelda launches that virtually reinvented the franchise and brought a huge number of new fans to it (myself included; I had never played a Zelda game before 2017) who would potentially be extremely interested in a remake of one of the more popular older games. They wouldn't be slipping compared to the Switch 1 Zelda renaissance if they took another six years from the previous title to come out with an original one, which would put it in 2029.

I'm not saying they don't have their issues; Pokemon launches since the late 3DS era have been somewhat notorious for performance issues (and of course aren't technically developed first-party, although they're certainly Nintendo exclusive, and I think there's a pretty strong argument that bringing them in house might actually improve the situation), and the Mario Kart entry for the Switch 2 seems to have been considered somewhat lackluster, but I don't think it's totally reasonable to start making long-term predictions yet. In the aftermath of the Wii craze, it would be easy to make similar predictions given the lows of the Wii U era, but they obviously came back pretty strong in the following generation, and there doesn't seem to be much evidence that they've come close to sinking that low again yet.

I think they tend to try to vary the order that they do major releases between generations. The Switch 1 era had Breath of the Wild as a launch title (that also launched on Wii U, which is easy to forget), and Mario Odyssey came up before the end of that year, and they re-released the Wii U version of Mario Kart rather than coming out with an original entry. After the huge cultural zeitgeist around Wii Sports when it was paired alongside a Zelda title for the Wii, they seem to have been trying to repeat that with somewhat quirky minigame compilations alongside major franchises; the Wii U had a weird theme park thing with the new Mario game, and they paired Breath of the Wild with the extremely forgettable 1-2-Switch and a co-op puzzle game that I don't think I ever heard of anyone actually playing.