I’m not planning to throw that watch away ever. So why would I be throwing my mouse or my keyboard away if it’s a fantastic-quality, well-designed, software-enabled mouse?
Because watch technology is mature and isn’t changing. Nobody’s making a better watch every few years.
That generally isn’t true of computer hardware.
In the 1980s, you had maybe a one or two button mouse with mechanical optical encoder rings turned by a ball that gummed up and would stick.
After that:
A third mouse button showed up
A scrollwheel showed up
Optical sensors showed up.
Better optical sensors showed up
Polling rate improved
Mice got the ability to go to sleep if not being used.
More buttons showed up, with mice often having five or more buttons.
Tilt scrollwheels showed up
Wireless mice showed up
Better wireless protocols showed up
Optical sensor resolutions drastically increased
Weight decreased
Foot pads used less-friction-inducing material.
Several updates happened to track changing ports (on PC, serial, PS/2, USB-A, and probably soon USB-C).
If wristwatches had improved like that over the past 40 years, you likely wouldn’t be keeping an older one either.
If you think that there isn’t going to be any more change in mice, okay, maybe you can try selling people on the same mouse for a long time. I’m skeptical.