Wow some of these post are bordering on severely mentally handicapped.
The triple A space is definitely shrinking, because of the rising cost of development and the demands on triple A games, eg high end 3d graphics, voice acting, online components.
Back in the PS2 days because of it's dominance and low cost of development you could release anything really and still eat well as a developer/publisher, however with the PS3 and 360 era you had the bottom fall out and developers like THQ were shuttered and as it stands now, launching a new AAA franchise is very hard.
There have been big closures of game studios in this generation: Lionhead, Evolution (though they got reopened under code master), Avalanche (they got reopened as well) and it's because gaming has gotten so big, the investors and there fore the companies don't want to spend 50 million to make 60 million they'd rather spend 100 million to make 150 million.
This becomes problematic when the game companies themselves are beholden to the stake holders and become increasing risk averse.
If game companies were happy making a 30 million dollar game and making 40 million it wouldn't be a big deal but if you insist on making 100 million dollar games then yeah you're in for it if you miss.
The Gaming industry is incredibly top heavy, just look at NPD, digital sale charts etc, the same games pop up again and again. Companies like activision/blizzard, EA, Sony, WB, UBI eat good on the lack of competition but we as consumers lose choices.
The bottom line is that the top heavy industry makes companies more risk averse and so we got sequel after sequel and reused assets so companies can make a buck or two and we the consumer get stuck with too many games that play it safe.
I see a lot of people talking about marketing doesn't matter...and I whole heartedly disagree
Not to say you can't overspend on marketing or waste money marketing something that's not wanted but unless you hit some specific check marks your game will likely flop.
There are legions of good to great games that didn't sell well, just last year Watch dogs 2 flopped compared to part 1, Dishonored 2 barely charted, Deus Ex was flopzilla, all 3 of those games are excellent but just being good wasn't enough.
As far as charts are concerned then yeah companies that don't provide data won't show up EG blizzard has their own distribution and don't submit to NPD, but more and more companies are giving NPD data, even MS is starting to give digital data starting next month which should make the charts even stronger.