I beg to differ...
I bought Doom on xbox live and really enjoyed playing it again (for hours). I also bought games like Golden Axe, Bomberman, 1942 (top down plane shooter), etc. Many old games i've played again these days, and most of them didn't loose their appeal.
On the other hand. There certainly are old games that are best kept as a good memory and if you ever dare to play them again, you shall be left wondering why you once thought they were so great, i give you that. It's just that Doom isn't one of those IMO.
It's good to have new and better looking games. Bad games were made years ago already, and they still make bad games today (maybe more than in the past). A good game does not equal good graphics, and good graphics do not make a bad game any better. However, good graphics certainly make a good game a lot more enjoyable.