Difficulty is pretty much what YOU make of it.
The reason games seem easier these days, is because
a.) games are MUCH longer
and
b.) games have exponentially more depth than their early NES/SNES counterparts.
Take a game like Bad Dudes.
Back then, Bad Dudes was hard as hell... because you had basically TWO attacks.. and it was pretty straight forward. Die three times, START OVER, erase whatever TIME you had invested.
However the game was what? 3 hours long when you beat it?
Once you had, you started over and it was just the same game. No extras, no various ways to play, nothing to extend the "fun". Once you mastered it, the game was effectively done and tossed into the bin of "beaten games" to rot for all eternity.
Now take a game like GTA IV. Sure some of the missions seem simple. But then again, it's because you have 100 different ways to tackle scenarios. If you fail one part, you get to start over and try a DIFFERENT strategy! It isnt about "starting over to do exactly the same thing over and over again until you get lucky enough to win".
In short, modern games are more about the JOURNEY than the Destination. The payoff is better because the presentation is better in most modern games, but since they have fantastic stories to tell and endless opportunities in game play, they want to let people actually enjoy that variety.
Ninja Gaiden can be quite challenging, but you have many different ways to dispatch your foes and even when you start over, no battle goes exactly the same as previous attempts, unlike in the NES days when there was really only ONE strategy and until you figured it out, the boss would just pwn your ass ten ways to Sunday.
Such things are not "fun" to me. So if EASY = FUN, give me Easy any and everyday.
I'd rather be having a simple blast than a frustrating "challenge".