> typical crystals in the 10-100MHz range

I think most quarts watches oscillate at 32 kHz = 2^15 Hz, high precision quartz watches at 8.4 MHz = 2^23 Hz.

> The actual problem is stability over temperature

Apparently, designers of these watches compensating for that somehow: https://en.wikipedia.org/wiki/Quartz_clock#Thermal_compensat...

> benefits from being kept at constant-ish body temperature

Some people take off their watches every day before going to sleep.

These high-end quartz oscillators are probably too expensive to use in commodity computers. Still, the cost shouldn’t look too bad when compared to a price or an airplane, marine vessel, or most military equipment.