The games are designed for the same age group as the games were designed for back in the greatness period of the Amiga.
The only difference is that kids now a days are a bit more spoiled and as such can't be bothered to play a game which requires them to replay a game level many times, even if there's quick save included too.
It also has to do with the fact that there are now a wider option for difficulty levels. Not every old game had difficulty levels but now a days most games do have levels, something which is nice for the companies since it allows them to appeal to a broader segment as the beginners can pick up the game and so can the hardcore gamers and noone will say it's too easy or too hard and not worth the money because of the difficulty. At least I think that's the philosophy.
I think though that quick save is a sort of cheat mode in itself, at least in action games. But then again, that's just because I'm not so spoiled as to expect quick save. It's a good way to make it through a game quickly as you don't have to replay much if you just save regularly. I've seen gamers play a game saving every 30 seconds. I myself do quicksave at times, usually I forget or go at least 5 minutes without a quicksave. Only time I quicksave more often is if the same point somewhere has been giving me trouble and I've tried way too many times to get past the place.
The games being too easy I don't know about though. Take serious sam. If you just select the right difficulty mode I don't think the gamer is born who could complete the game easily on the hardest level without some kind of cheat.