With so many gamers from the '80s and '90s growing older, retro gaming has been a growing market. Game companies re-release old titles on new platforms so fans can play their favorites without having to find and dust off their original systems, and developers love doing it because it takes almost no time to reproduce these games compared to the months of development for new games on the current generation of consoles.
Before game consoles had access to the Internet, the only way these titles could be released was on a compilation disc, most times costing around $30 for a collection of 10 to 15 games. With the current generation of systems, the Xbox Live Marketplace, PlayStation Network, or Wii Shop Channel can be accessed to download the most popular titles individually for a cost of $4 to $15, which eliminates the costs of disc production and shipping, resulting in bigger gains for publishers for less work.
Don't get me wrong: It's nice being able to download the games I can't find and have them saved somewhere I won't lose them, but it was the selection that I loved about compilation discs. I would have never played classics like Joust or Centipede without them.