That was because the developers didn’t do the extra bit of work to include additional rendering features. They didn’t do hardly anything for PCs in those days, sometimes they didn’t even include Mouse and Keyboard support and required a gamepad to play the game. Also they had to deal with Windows Vista and Games for Windows Live.

I get what you’re trying to say, but you are intentionally leaving things out, which is disingenuous.

Complaining about not using your whole PC is way less of an issue than complaining about really bad performance on hardware that definitely should not be struggling.