umm… we’ll have to disagree there. I think a lot of modern, high-end games were built before 2004.
Current game physics is the same math as 20 years ago.
Current game graphics is the same methods as 20 years ago (but more of it! MUCH more!)
Current game networking is the same algorithms as 20 years ago.
Current game mechanics are, if possible, even less rich than they were 20 years ago, at least for comparable blockbuster titles.
Current game software engineering has perhaps caught up to where the rest of software engineering was 20 years ago by now 