http://kotaku.com/5820632/why-is-the-new-xcom-a-shooter-because-strategy-games-are-just-not-contemporary 
 
It's not that Strategy games are dying it's that the platform thats good at them PC is racked by piracy which has devistated PC Exclusive Triple A development over the last 7 plus years. 

Crysis 1 was the last only on PC big budget Triple A FPS game a console could'nt do and it aparently sold barely over 80,000 units in it first week on sale. some of that was down to intimidation over specs but the bulk of it was Piracy. 

For those who say what about Crysis 2, None of the open areas in that game are a fraction of the size of the ones in crysis 1 and there are an awful lot more loading screens as well. 

Crysis 2 is console constrained they simply don't have the grunt or maybe more importantly the memory to deal with crysis 1.

RTS games are not as taxing but console controls just don't work for them.
as a result funding for big RTS and Strategy games has seen a serious decline comepared to the late 90's as an example. I'm sure Starcraft 2 only got made due to Blizzards independence from activision and the money to be made in south korea. 
 
The The Only two Big rts Devs left I can think of are Relic and Blizzard