It's because they're fun to play and can create lasting memories, from my first memory of having either a sega mega drive or master system (can't remeber which one it was but it had sonic built into it) downloading it years later on the wii and remembering the 1up you could get by jumping through the fake wall in the second level, playing tekken, street fighter 2, mario kart, goldeneye and others with my friends years ago. I fell away from gaming for a while then got a n64 myself a few years later played ocarina of time for the first time which absolutely blew my mind at the time and i've been a gamer ever since. Had a lot of consoles through the years from the ps1, 2 &3, the xbox and 360, and every nintendo one expect the 3ds and the wiiu. Now i'm a massive Zelda fan that's been waiting patiently for tears of the kingdom for 6 YEARS lol.