>>11862832 (OP)PCs in the early-mid 2000s had radically different hardware from consoles other than the OG Xbox, and there was a huge rift between the capabilities of low-end and high-end hardware. Intel graphics back then didn't even support goddamn Hardware T&L.
There also wasn't a concerted effort to turn PCs into a streamlined, console-like platform until Steam got popular, and that was met with resistance at first. There was GFWL too, which everyone hated.
There's a bunch of factors, but I think it's easy for people to forget how terrible most early-mid 2000s PC hardware was since games like Doom 3, Half Life 2, and Far Cry existed.