Another fact to consider.
I have read that in pre revolutionary France the title of marquis had gradually become little respected for some reasons.
I think that the title of marquis had become adopted by many people who had no legal right to it.
I once read that in some noble families it was the practice for the gnerations from father to son to grandson to great grandson, etc. to alternate the use of the titles of Count of . and Marquis of so people could tell who was being mentioned.
If such a family had the legal right to use the title of marquis, higher than count, wouldn't each person who inherited the right to the title marquis use it? Unless the title wasn't considered to much, or any, higher than count.
And if members of the family used the title of marquis without legal right, the ones who only used the title of count would be merely obeying the law instead of breaking it.
I have read that before the revolution it was common for people to rank coronets inh their coats of arms of higher ranks than they actually, so the real holders of those ranks felt obligated to use heraldic coronets of ranks higher than they had, and so on. Thus I can find easy to believe that many people falsely claimed to have the title of Marquis and that it became little respected.
There is this:
During the Ancien Régime, there was no distinction of rank by title (except for the title of duke, which was often associated with the strictly regulated privileges of the peerage, including precedence above other titled nobles). The hierarchy within the French nobility below peers was initially based on seniority; a count whose family had been noble since the 14th century was higher-ranked than a marquis whose title only dated to the 18th century. Precedence at the royal court was based on the family's ancienneté, its alliances (marriages), its hommages (dignities and offices held) and, lastly, its illustrations (record of deeds and achievements).
Later Napoleon created a new system of nobility, without the title of marquis.
This was carried out in 1808, by a decree of March 30, 1808 on titles. Napoléon created a full-blown hierarchy of titles: prince, duc, comte, baron, chevalier (each qualified as de l'Empire: prince de l'Empire, duc de l'Empire, etc). For some reason, Napoléon found the titles of marquis and vicomte ridiculous, and never bestowed them.
One could receive a title without exercising one of its enumerated functions. The title of marquis was not used during the First French Empire, and it therefore became very fashionable after the Bourbon Restoration, since it was not perceived to be tainted by the Napoleonic creations.
Adn Iread somewhere that Napoleon didn't grant the titleof marquis because it had become little respected before the revolution.