[lodovic]

That's really not the case. Check the wiki page for the top games in 2005. Many of these games are still around in an upgraded form.

[teamonkey]

In most cases, a re-released game is an entirely new game SKU using the same IP, just as a movie remake is a new movie based on a previous one. And similarly, once released, most rereleased or remastered games have a short tail.