No you're not. What fails the most frequently are the microswitches, anyway.
I wonder if wireless mouse using the ball would last much longer on battery. I guess, it could. It still uses a led light internally, but I don't think it needs to be that strong.
A wireless mouse could last indefinitely, if it used magnetic resolvers instead of encoders (and siphoned off a bit of the voltage to recharge the battery.
I expect you could also make a self-powered keyboard with a coil and magnet under the spacebar...
I don't recall any of the mechanical mice I've taken apart having LEDs inside them. IIRC had 3 rollers/wheels which physically touched the ball and that was what "sensed" the motion. I'm talking 90s sort of era though, so it's possible more recent mechanical mice were designed differently.
Rollers were connected to wheel with a plenty of holes, and there was a led + fotodiode that was used to detect the motion of the wheel. At least that's what I thought back then. (> 20 years, heh)
Most basic 80s and 90s mice used LEDs to track the ball, via secondary wheels. They’re tiny and don’t look like lights so you probably overlooked them.
I wonder if wireless mouse using the ball would last much longer on battery. I guess, it could. It still uses a led light internally, but I don't think it needs to be that strong.