A lot of these people would be willing to give any amount of money to actually play the games they used to spend hours playing as a kid. Nothing can beat the thrill of Space Inavders or the addictive fun of Pac-Man . The same principle can be used for the other classic systems, i.e. NES, Genesis, SNES etc. Just for people to be able to play the games they once played to death is good enough reason for them to buy reissues. Just to experience the game again.
People also like to play classic games so that they can relive childhood memories.
I know that whenever I play Sonic the Hedgehog today I'm filled with a warm fuzzy feeling, along with many memories of when I was in first grade and playing it for the first time. As a matter of fact, most of my friends remember playing those games so much, that they could even hum one of the songs from them for you, but I digress. Playing a game you loved as a child always gives you that sense of comfort and security that does not exist as a teenager or an adult. In order to completely understand the excitment of the FFIV re-release in particular you have to understand a few things first. The game originally was cut to shreds when it was released in the US in 1991.