"Free market" is a myth from lolbertarian Randroids. The most powerful corporations have the ability to generate demand for their products through misinformation, hype and all other methods you all know about, and in most cases the only reason they haven't literally become monopolies are laws. They define the parameters for the rest of a sector in the market, and thus they rule it and aren't afraid of anything.
That is, until someone big does some wrong choice and years later the consequence comes as the bubble blows up and the crash begins.
The 21st century will ironically be a time when capitalism will cause more intellectual, economic and technological stagnation than shitty planned economies with potato shortages did in the 20th.
I really don't know other then that companies like EA probably don't know the niches and don't want to. Not in their business model. It's not like the games they make will ever be obsolete until they make the sequel to said games, so basically the balls in their court so they don't really care what a company like Paradox or Matrix is making.
Actually, there are more interest groups benefitting from the maintenance of the current AAA business model. If suddenly big companies started carving niches and found a more efficient model that reduces their dependence on massive PR investments, several groups would be threatened by such a shift. Besides, they prefer to stick to their comfort zone, to what they are used to do. Corporations are not the uber-perfect flawless business model that some people think they are. Because what is profitable for a corporation is not necessarily advantageous for, say, its PR director, among other things. As a rule of thumb: the larger a business become, the least it will be willing to innovate.