system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40k] What do the Space Marine chapters get out of fighting for the Imperium?

So the Imperium gets an army of 8 foot tall super-soldiers and the Marines get.....to die gloriously? Do they even get paid? Why haven't some of the Chapters just followed Ultramars lead and established their own mini imperiums? Just make their own deals with the mechanicus and let the Imperium drown in a sea of tyranid and ork.
gpt
They are, for the most part, thoroughly indoctrinated into the imperial cult and would never question the will of the emperor.  The ones that still maintain some semblance of autonomy want to fight the enemies of the emperor anyway, even if they didn't have to.  They literally live to fight.  They have no desire to hold lands or own material trinkets.  Monetary wealth is of no value to them.  Even if a chapter did commit the unthinkable heresy of trying to carve out their own empire they would be attacked by chapters specifically created to combat traiter space marines.