Not really. I still play Master of Orion on a regular basis, and it came out in 1991. Same with the original Civilization from 1990.
The reason I can still play these games is because I have a copy of them. That's the point in question here. Do I really have a copy of Portal 2? It's on my computer now, sure. But will I be able to fire it up and reminisce in 2031?