Yes, they can. MCU proves if you have a winning formula, you can just continue it indefinitely. Star Wars also shows that some fans will revolt if you try to give them anything different. Personally, as a fortysomething that grew up on Mario and Zelda games on NES and have owned four Nintendo consoles (NES, SNES, Wii and Switch), I still like some of the same types of games I liked 30+ years ago. I've recently gotten into the Fire Emblem series too. Some tastes have also expanded but I still love Mario. Breath of the Wild is still in my Top 5 favorite Switch games. You should really give that a try, definitely more fun than an Assassin's Creed game (I should know, I've played two). The thing you should understand, OP, is that Nintendo makes ganes for everyone: they aren't bound to THE Demographic (18-35 men).
I haven't played Pokemon yet but that looks like a lot of fun (needs a Hard Mode though). My sister has loved Animal Crossing since City Folk, but New Horizons is my first one I've actually played alongside her. As someone who's 41, your tastes may change but the core of what you like doesn't really change much. As Yui Hirasawa said in K-On!: "Fun things are fun".