Oh, don't get me wrong, I don't think 100% of them are easy, just the majority. Batman: Arkham Asylum and Arkham City, for example, are both very difficult games, in my opinion. The majority of games made today though seem to follow a trend "Look good, leave gameplay as an afterthought". Which constantly proves true everywhere I look, Ace Combat Assault Horizon, Armored Core 5, Burnout Paradise, Mirror's Edge, Alan Wake.. (games with generally low difficulty and bland game mechanics). ALL have examples of precisely what I mean. All of them seem to be more worried about how the game looks than how the game plays. Leaving many a fan either disappointed or just ashamed to have liked the game series in the first place.
Square Enix's Final Fantasy is another great example of just what I mean. I-III it was almost solely about the gameplay experience itself and was hard as hell, IV-VI it became a little more about the look of the game, easing the throttle on what made the games so difficult to play, still keeping the gameplay experience in-tact.. VII is where it began to take a huge turn. Going more for looks than gameplay, moderate difficulty level and an mildly interesting battle system, leaving fans disappointed or loving the game even more by stepping in another direction. VII-X same way, leaving a lot to be desired from every game as well as a lot to love about them.. Then XII goes almost completely on looks, becomes love it or hate it, and thus sends the game in its downspiral.
Another example would be a good chunk of FPS games on the market today. The games used to be all about the story, whether it be horror (FEAR, Doom, Quake, etc.), playing a war hero (Medal of Honor, Call of Duty, Halo), playing a role (Dead to Rights, Max Payne) or just being wacky and having fun. (Conker's Bad Fur Day) Now? It's a tacked on campaign that takes little effort and no time to play through, then to nothing but online gameplay with better graphics and new maps with each new installment. (Black Ops 2, Halo 4, etc.)
My point is more of a desire of what made games good in the first place and less of showing off the power of the system.