If you slip 4 or 5 years around now the tech barely changes. You can't really tell much the difference between a game delivered in 2018 and 2023, especially if

If you slip 4 or 5 years around now the tech barely changes. You can't really tell much the difference between a game delivered in 2018 and 2023, especially if some polish is later added. Whereas back in 1998, there is absolute night and day between 1994 tech (DOOM) and 1998 tech (Quake 2), to the point where the latter makes the former look ancient and almost unplayable in comparison. Keeping in mind also that tech moved so fast that "serious" PC gamers would look to upgrade their PC on a much quicker cycle, every couple of years was a game-changing upgrade such as Pentium chips or DDR RAM, or some other new tech that just blew away the previous PC generation. Games companies didn't have the luxury to slip years and still deliver on what they started, and any "engine change" would have been far more impactful against that background, and also keep in mind that "changing engine" back then meant from scratch engines not swapping, say, between Unity and Unreal or some other off the shelf stuff.