Because the guys on the ground who would prefer not to be bombed happen to have surface to air missile systems that are just as good at locking up our older fighters, especially on IR.
Further, there will be no more F-22s. The Obama administration has cancelled the program after 187 were built, saying the F-35 should be able to fill in the gaps. Which they will probably also now be cancelling.
187 F22s should be enough with their high kill ratio. The F35s would be used off carriers or whenever the F22s are busy doing other patrols.