Or...perhaps they will wait for Marvel to pull a late 1990's W.B. and implode on themselves by making terrible movies (FF 1 n 2, Spidey 3, Hulk 1 n 2...should Spidey 4 fail, that franchise as we know it is done; none of the other in development projects look likely to happen or promising or both; soon Iron Man will be the only large Marvel franchise alive, with an xmen origin here n there) and then W.B. pull an early 2000's Marvel and swoop in (with Green Lantern in 2011, Batman 3 in 2012, and Superman sometime after), seize and hold a virtual monoply over the market, and pretty much run the show.
Learn from history. In the late 1990's, Marvel sat on Xmen and Spiderman while W.B. punched out Batman films. W.B. got more money hungry and film quality went down, eventually so much that it killed what was once the worlds greatest franchise; in the end it paid for Marvel sitting on the properties because when they eventually were made, they were quality films. Whose to say the cycle isnt repeating itself, but with roles switched?
Lets be serious. Should W.B. race to catch up with Marvel when the stuff Marvel is producing as of late is crap, outside of Iron Man? Of course not. Why not wait for the project to develop into a quality project, while Marvel burns themselves out. Look at their slate; the ONLY promising franchise is Iron Man. When the rookie studio mishandles properties/makes films nobody wants to see (Thor, Hulk 2, ect.) they WILL lose money.