Nostalgia does play a part for people who are replaying games. But this works both ways, some games stand the test of time, while others should disappear into obscurity. A good example of this is Transport Tycoon (deluxe) which is as fresh as it was in 94/95 and can still suck you in for hours/days/weeks! Another one is heroes of might and magic 2, newer versions looks better and have a small feature set upgrade, but the game is infact the same. Warcraft II doesnt stack up as well

and carmageddon only has nostalgia left.
I often think of older games like I do old films. Does it really matter if they didnt have cgi in the 50s and used stop motion or puppets for special effects? My imagination can fill in the blanks and I enjoy it just as much as I would a current blockbuster.
If I think back to the early 90's when 3d started penetrating the arcades, people loved the tech, but still wanted to play bubble bobble. Today is no different.