Xerox invented basically everything about modern personal computers, from point and Wickard to intuitive interaction to bit mapping to ethernet to laser printers. But it’s unfair to say they blew it by not marketing their prototyp. The cost would’ve been prohibitive. It’s not a personal computer if persons can’t afford it.
IBM contrarywise got lucky. It hit at the exact optimum moment. You can’t plan that.
I don’t think Xerox invented this. They developed the PARC system.
PBS did a series on the history of computing and had a guy in a video clip demonstrating a mouse, point and click, WYSIWYG, and Icons. I think he was the pre-curser (pun intended) to everybody else.