Xerox PARC

Beginning in 1970, Xerox's Palo Alto Research Center built the future of computing: the graphical user interface, the mouse, Ethernet, laser printing, and the Alto, a personal computer roughly a decade ahead of anything consumers could buy. Yet Xerox, whose profits flowed from copiers, captured almost none of it. When Steve Jobs visited in 1979 and saw the Alto demo, he could not believe the company was leaving it on the shelf. Apple, Microsoft, HP, and others would commercialize what Xerox's own researchers had invented first.

This is one of the sharpest cautionary tales for anyone sitting on capability they aren't shipping. It pushes founders and operators to confront why a profitable core product can quietly smother a better idea, and how value actually gets captured. The case names a specific tension and leaves you to wrestle with the resolution yourself.