It's pretty simple. Lets use Nintendo as an example:

Core Gamer: "Hey you should try this new game I just got, It's called Animal Crossing"
Casual gamer friend: What's it about"
Core: "You move into this town filled with Animals, you can decorate your house and fish, and catch bugs and stuff"
Casual friend: "Ok, sounds kinda fun"

----------------------------------------------------
Core Gamer: "Hey you should try this new game called Pikmin"
Casual friend: "What's it called?"
Core: Pikmin...
Casual: Pikman? What do you do?
Core: You're a space man who crashes on this odd planet, you use plant creatures called Pikmin to collect your missing ship parts so you can go home"
Casual friend: "They are called Pikmin?"

I'm not ripping on the general public but that was seriously and actual conversation when I tried to explain Pikmin before. Plus, if someone is watching you play both games, which do you think will draw more interest?

I see nothing wrong with it.

Most people are sheep and only do what their peers do, because it's the "in" thing.

I find that "main stream" games sell well due to the fact people know what to expect. I'm pretty anal when it comes to controls in games and when i see a new FPS i have no idea how it controls or plays. But i know i can buy any cod and know the game will control perfectly for me. But when i have played crysis, BattleField, killzone, and countless other FPS games the controls are horrible in them and it leads me to stop buying any shooter games other then CoD.

The same works for me and i assume others when i want to buy a JRPG. I want tradional battles and no JRPGs due this anymore, so i just stopped buying them. I was really looking forward to Ni no kuni, but i tried the demo and the combat system was horrible.

Another major problem this gen which lead to reduced sales in games, was how they would change the camera angle or Fov in sequels. Saints Row the third and borderlands2 both changed the camera/fov and the games became unplayable for me. Both series i will never buy again. The newer cods also did this and why i never bought them.

Say whaaaat? I thought that was the best thing about the game. Hands down best combat system of any RPG I've ever played.  But yes, you do have a point. 

Gamegears said pretty much what I wanted to say. :/

well, high price points make for a picky consumer, 2 new games is $120, thats alot so it makes sense the majority stick with those popular know what they are getting, titles year after year, though you or i might not like some of those popular titles, they still sell.
i usually end up with all of them at some point, just some i wait for sales, a good priced used game, or mark downs before buying, i couldnt afford a quarter of my games without doing that.

edit: plus too COD is maketed allover tv and everywhere, accessories and everything. the name is well known. i didnt see that much with the uncharteds or others that are great games as well. just an observation.

I think X is getting pretty decent hype for an RPG, and at e3 we saw pretty much no combat, just exploration and quasi-cut scenes. I'd say X is the most hyped non-FF RPG in memory. It reminds me of the buzz that FF7 was getting pre-release, though not quite there yet.

The thing is, the games that you mentioned that get high sales are good games. Very well executed games with broad appeal. When I opened up my Wii U at Christmas this past year, my 72 year old mother loved COD. She liked the concept of being a soldier and shooting people. It is, quite simply, fun. Personally I will spend 140hours+ on Xenoblade finding the extra skill trees and completing my collectopedia and following what I think is an amazing and complex and unique fantasy/sci-fi story. But most people won't. They would say I was wasting my time and should get some fresh air. They're probably right, but it's what I enjoy even if most don't. But just because my favorite game is more complex, doesn't mean it's better.

Is that a vgchartz reality show?

We'll most of us are here or on other gameforums talking about videogames... Did you think we had time to actually go out, buy and play those games? Trolling MS, Sony or Nintendo takes a lot of time..

Avatar = $2.7 billion
Transformers: Dark of the Moon = $1.1 billion
Star Wars Episode 1 = $1 billion

versus...
Slumdog Millionaire = $0.14 billion
The Departed = $0.13 billion
Spirited Away = $0.01 billion

It not just games. It's a problem with society in general.