"After everyone else"? Well, there was the Mac. And there was TopView. And there was... who, exactly, is "everyone else"? There were workstations like Silicon Graphics, but they didn't even pretend to be available (affordable) for the average user. They weren't competition for the PC. On commodity hardware, it was Windows and TopView, and TopView was... not very useful, to put it charitably.
The PS/2 was a technically better product. It was also IBM's attempt to put the genie back in the bottle, so that it could sell hardware at prices considerably above the commodity level. Technically better? Cool. Not having to pay several hundred dollars more for your hardware? The market thought that was even more cool.
