User blog comment:B214/Volume 23 discussion blog/@comment-31764731-20170420000500/@comment-30048084-20170420200224

The Aristocratic society of the Underworld will not collapse yes there are a lot of reincarnated devils in comparison to the High-Class pure blood devils however you are forgetting something the remaining how many million not High-Class pure blood devils.

A key tenant of their Aristocratic society is maintaining pure blooded High-Class devils of the 72 pillars. Remember some of the 'extinct' pillars of the 72 are not actually extinct however their are no known pure blooded devils remaining to maintain the bloodline.

Purity will never vanish from their society Issei and Rias are an exception and we don't actually know the repercussions of that choice on the Gremory's status in the pillars. The fact that Millicas remains is the deciding factor.

@Bashkim1234 ignore the red part and concentrate on the green part. It has never once been stated that the reincarnated devils want to gain political power because they trust the Yondai Maou system and have no reason to question it remember that it is one of those Maou that made the evil piecec system.

It is common that the minority rules over the majority that is the nature of this world even if you democratically elect a government are they not a minority that you chose to rule over the majority.