I'm pretty sure there are more local multiplayer games to choose from today than there were in the old days if you count Steam, Switch, and indie games. Not to mention older games themselves. I'm always keeping an eye out for new multiplayer games my wife and I might both enjoy, and there are so many to pick through on Switch!
It's true enough that a certain slice of games pushing shiny graphics and/or online multiplayer have de-emphasized splitscreen gaming, including within the racing genre, but if you're merely after local fun in general, there's a lot out there you may be overlooking. 👍 Party games like Overcooked 2 and various wacky physics games, 4-player brawlers, or co-op platformers are ubiquitous, honestly.
Just in the racing genre, there are retro titles like Horizon Chase Turbo or the upcoming Hotshot Racing, GRIP if racing combat is your thing, Redout, FAST RMX or Mario Kart 8 DX on Switch, etc...