Fox had some situation where they needed to make agreements with their affiliates. There was talk about starting Conan on FX and moving him to Fox when they could strike a deal with the locals. I guess this bypasses that.
Conan wanted the Fox affiliates to all agree to show him, but some of the affiliates were worried about losing money from their syndication deals for Simpsons/Friends/Seinfeld.
Conan and Andy were also less than thrilled about Fox's cancellation of Andy Richter Controls the Universe.
Leno's average viewer age is 56. Lopez's average viewer age is 33. Not hard to figure out who Conan is targeting.