To piggyback on that notion, I think that gamers fall into two groups nowadays - gamers who play to be challenged and gamers who play to relax. If people want to be challenged while playing a game, there is a sense of accomplishment that comes from beating a difficult game or a difficult section of a game. But, I play to relax. My life is difficult enough as it is.
I admit, I've definitely changed in my old age. I used to start and beat everything on the hardest mode available, but I just don't have it in me anymore. I finally stopped when Max Payne 3 beat me down enough to see it wasn't fun anymore. I still start all the Halo games on Heroic, but that's about it for me. I actually shy away from games that mention extreme difficulty, as I just don't have the patience to be frustrated by something that's supposed to be fun. No shame!