Except there usually aren't a couple thousand others, since apart from a few [sometimes undeserving] popular tracks and games, there are maybe two or three remixes for a given song, if you're lucky. Heck, this also applies to how much attention the games themselves get. Look at the list of most remixed albums for the PS1; Final Fantasy VII has a whopping eighty-seven remixes, with an insane drop off to Xenogears' thirty-six.
And sometimes the original has the raw notes down but the instruments aren't as good, usually because of the technical limitations of the system its source game was on. The ending for Super Metroid, for instance - one of my favorite songs of all time, provided the instruments sound more authentic than what you'd find in a SNES game.