Please let me make clear one deceptive point. What you call those advocating reform mainly were not reformers but people who wanted to go backwards.
Louis XIV was a reformer. He created what was called the administrative monarchy which, in fact, was more open to new talents than the reform advocated by the old privileged nobility. Louis XIV promoted many people from the bourgeoisie.
The program of these so-called reformers was a kind of usurpation : the equivalent of the house of Lords claiming to represent the people without the house of the Commons. That's what they finally tried in the years 1787/88 : trying to go back 150 years earlier. And it was a disaster that contributed more than anything else to the will of many people to get rid of such a nobility when, just after, the revolution broke out.
These so-called reformers did even enforce their ideas during the first years of the regency of the duke of Orleans, during OTL Louis XV's minority. It was called the polisinody. And it was such a mess that the regent quite quickly put an end to the experiment.