people have been saying for at ten years that shooters are atired out genre and yet they keep coming back. they'll always be around, like any good gmae or genre.
I can't think of a time when shooters haven't sold well. Ever since developing an FPS in a 3D environment became possible they've been extremely popular.
Which is why I think people who expect shooters to die down in popularity are slightly delusional, shooters will likely always be tremendously popular and some of the industry's most profitable titles. As long as there are young males who are attracted to violence in their entertainment (which has been a staple of our sex since, I think, the beginning of time) shooters will always have a large audience.
I do agree that the market is over-saturated with bad shooters, but at least this year we've got Bioshock Infinite and Borderlands 2 coming our way.