You can try and blame those TV shows that show a dude selling an "NES 01" for 4 figures or whatever but remember, TV FOLLOWS trends, it doesn't create them.

The true culprit, the real seed of the issue was the Angry Nintendo Nerd. Not "James" himself, but him and Mike Matei working together on the ANN then turned AVGN.
James and Mike put together those first few videos and then they were caught by Gametrailers. That's a LOT of modern gamers looking at videos about old-ass games thinking "Yeah, I had an NES as a kid, that actually WAS fun. I shouldn't have sold it to buy a SNES/PS1/whatever".

Then when the show was picked up by Screwattack it only got worse. Even more gamers of all ages, both young and old being exposed NOT JUST to AVGN but Craig himself was also a big retro gamer. Then came Moviebob with the Game Overthinker and Pat the NES Punk and-

Basically a bunch of nerds got reminded of their childhood and the younger nerds thought "hey these consoles are cheaper than a PS3/360 because they're literally 25 years old". Add to that the thousands of Flash animations and games based on old SNES/PS1 games stuffed in Newgrounds and the underground retro gaming scene was born. Of course nothing stays underground for long because when a market shows up it's infiltrated and exploited, but the creation of that big retro market can be traced directly back to James Rolfe showing up at Mike and Bootsy's apartment in college and seeing them play on a dusty old NES instead of new modern games.