Most popular Wii games had significantly different control schemes than what is available on a standard PC. Afaik, dolphin was primarily used for things like Smash Bros but other system sellers like Wii Sports, Wii fit, and LoZ: Skyward Sword just wouldn't work at all. Even Mario Kart was typically played with motion controls, because that was new and exciting for home consoles at the time.
Contrast that to the Switch where most system sellers can be played on a standard controller without a gyroscope, the threat to their bottom line is much higher.
The wiimotes are just bluetooth and the tracking is 5 LEDs. I've used candles instead of the sensor bar before. You can buy a "dolphin bar" for $20 and use your wiimotes on the PC. It works great. I dumped my wii games and haven't touched the console in years.
Yeah I've used the candle trick with a Wii before too, but that doesn't mean it isn't a much larger barrier for entry than Switch games working most of the time with just a standard controller (and therefore keyboard mapping). As for controllers, I don't think I even had bluetooth in a desktop PC until somewhat recently (~3 years ago) when I paid a little extra for a motherboard with WiFi 6 and BT built-in.
Contrast that to the Switch where most system sellers can be played on a standard controller without a gyroscope, the threat to their bottom line is much higher.