You do need CCAs.
Even from an air combat perspective alone, being able to engage from multiple geometries is more valuable and useful than firing longer ranged missiles from fewer locations. Mlst The benefit of reach can be used to keep enemy units at bay, but thats only if you can pin down all the units engaging you back. The problem with having lesser points of engagement is that opposing units left unegaged will quickly compress your engagement timelines. You now have less ability to prosecute follow on shots on individual targets of value too. So unless youve got an equally distributed force, the disadvantage is hard to make up.
In combination with having more engagement options comes the added benefits of:
-Sensing
-Distributed EW, which is taking the place of stand in jamming.
-Resilient LOS based information networking and relay nodes
-presenting so many targets that you can, essentially, hide your shooters in plain sight
The benefits and vastly expanded options of having CCAs is becoming par for course even for countries without much money. Not having them puts you at an inherent disadvantage even if you can fly higher and shoot longer ranged, because at a certain point in the engagement, you will be outmanuvered or run out of the airspace by being unable to put up the same amount of combat mass.
I should also add that i remember reading most actual AAM engagements happen at high subsonic to low supersonic speeds and altitudes generally not as high as we think (sub 40 k). That altitude and speed decreases as you near the target as well due to renegagement timelines and defensibility