Switch did get a lot of extra new games because the Wii U flopped. Mario Kart 8 is currently their top seller and most Switch owners never got to play it on the Wii U. Splatoon 2 and Mario Maker 2 feel like iterations on the same game, but since they started on the Wii U they are also new to most people.
I don't think "Switch 2" will benefit nearly as much from Switch ports, but I do think it would be a good idea for them to port and remaster even older games. I am ready, willing and waiting for the first 3 Zelda games to get the Link's Awakening treatment. And of course they could actually remaster Mother 3 and release it worldwide. They have a hell of a backlog of potential ports that go back further than the Switch and Wii U.