Indeed, the patent wars are in full swing. Newcomers can expect to be frozen out. Apple , Microsoft, and Google may agree to not sue each other into oblivion and gang up on any newcomer. Perhaps they will start acting like a cartel.
"I'm here to destroy [Google]" -- Steve Jobs[2]
Maybe not the coziest of cartels.
[1] http://battellemedia.com/archives/2005/09/ballmer_throws_a_c...
[2] http://9to5mac.com/2012/04/05/biographer-disputes-google-ceo...
Bickering amongst the titans of tech doesn't mean they won't gang up on issues they deem to be mutually beneficial, and often those are at odds against startups.