That article pretty-much tells the tale as I remember it, even if in super-condensed form. The IBM PC went hard for the business and 'high-end consumer' markets, and really whiffed upon everyone else who was curious about getting in to computers, but didn't have such disposable income. And then Bill Gates came along, who managed to rip off the Mac OS with relative impunity, and absolutely nuked IBM's chances of dominating with its own next-level OS and GUI.
Shareware Doom played from a single floppy was amazing, though. What an incredible breakthrough for those of us who'd only known laggy wireframe 3D simulators played on older 8-bit machines.