Since most Dungeon Owners and their despotic Mangers at best neglect their Monsters, and at worst abandon them to the mercies of Reaction Chart Old School (drop loot and food to avoid combat) or Kill-'Em-All Hack-n-Slashers (who don't even get a name until 3rd level), it has become increasingly necessary for monsters to band together despite natural antipathies brought about over competition for resources (Monster on Monster crime has been an under reported aspect of Commercially Operated Dungeons for decades, if not centuries).
Is it any wonder that while many Adventurers have become softer-hearted, and some Monsters have found a soapbox from which to decry their oppression (workplace injury rates for Monsters do not take into account wounds or fatalities caused by Adventurers), Dungeon Owners are switching to a Monstrous Dungeon model, where a living macroorganism (Giant Mimic disguised as a Dungeon) is purchased from Skunkwork Wizardry sites and replaces the need for construction crews and Monster employees. The Dungeon-Monster simply grows as it is fed, with the occasional stocking of trinkets is performed by off-site service contract personnel (often Humanoid, or even Demi-Human or Human veterans unable to adjust to commoner life after all of the killing).
Dungeon Politics is a complex, multi-sided issue, but one thing is certain, Dungeon Owners are getting something out of the cycle which cannot easily be sussed out; if it isn't money, what is the draw?