Fedora was not the one making the decisions in regard to the rather specialized area of initial boot. Why that is can only be speculated, but I would hazard a guess that when there is an incentive conflict between what is best for redhat and what is best for fedora, focus of both will go where they align. Path of least resistance and all that.

I would also guess that the small number of developers that work within such niche area was basically all hired by redhat during the earlier days. Not with nefarious intention mind you but simply out of good business practice.