I won't rest until the average microcontroller in an optical mouse is more powerful than a Cray 1.

A lot of touchscreens meet that requirement. Turns out it's often cheaper to solve problems with algorithms than avoid them by design.

try as you may, but that mouse will never work as a lounge center piece.

There are millions, if not tens of millions of USB and PS/2 keyboards and mice out there powered by Cypress MCUs with 8051 cores.

That's a lot of cores

Nordic dominates the market for keyboards and mice. Programmable MCUs with BLE radios are required for any wireless devices.

Some gaming mice do for running RGB lights, macros, or whatever.