I'd be willing to bet that if Nintendo is as serious about pushing the Switch's portability angle, that we will get a main series Pokemon game on there at some point but I'd wager not for another two years. Game Freak isn't going to want to move until it's safe to do so, but they are pushing the limits of even the New 3ds. The 3ds is a system thats while getting many new iterations, has been out since 2011. I'd bet Gen 8 will be on the Switch, unless there's some serious breakthrough on the 3ds.
oh absolutely. gen 8 will not be on the 3DS. it will either be on the switch or, should they make one, whatever the 3DS’ successor is. The 3DS is a very dated piece of hardware and even with the New 3DS’ power boost it’s too weak compared to today’s standards. I mean, shit... in the past six years, technology has advanced so rapidly it’s silly. Nowadays, most people carry what’s basically small portable computers in their pocket... doesn’t really make the 3DS look good honestly.
meanwhile, yeah, gen 7 will stay on the 3DS (and hopefully that includes more than just USM). and i don’t blame them for that. i can’t imagine learning to code for an entirely new system mid-generation. upgrade graphics. code compatibility for the 3DS. it’d take way more than a year. and like you said, safety... switching over to the Switch wouldn’t be safe. the expectations for Pokemon on the switch would be astoundingly high, so they may as well wait for a new gen instead of rushing mid-gen and dropping the ball.