I think on one hand, it's true that as we get older, candy doesn't taste as sweet anymore, and video games don't equal the pinnacle of happiness. On the other hand, I have noticed that ever since games on consoles have gone to 3D, it seems like so much energy is put into the graphics and animation that less is put into trying to make the game fun. There are so many 2D games that were just fun fun fun to play and to this day still are. There are some good 3D games, but I think that maybe 2D games can have a betetr chance of being fun, because many gamers think in limited dimensions. I know mario brothers never prepared me for being blindsided in FPS games.
Also the challenge seems to be less. I never beat SMB for NES, but then SMW for SNES came out, i beat it no problem and wondered if they intentionally made things easier for little kids (like < 5). Remember Bayou Billy? That game was impossible! The dudes were as tough as you and you kad to take on like 4 of them at a time, and that was the 1st level. I never got past level 3 in that game, and after beating it with the game genie, i don't see how anyone could ever do it.