They accept it as inevitable. Pay certain people the right things. Don't say things about certain other people when they try and take advantage. Respect this person or that person or you wind up dead. That's all predictable, to a degree. Obey the "rules," no matter how perverse they may be, and you have self-preservation.
"Here's a gun with no bullets, go run out into that field and get your ass shot to death for no reason, or hunker down here and get blown up" is not predictable. At that point, self-preservation is out the window.
And it's all about self-preservation, as with any selfishness. And all that's necessary is that enough people judge that their lives are better spent fighting inside of Russia rather than getting blown up outside of it, if for nothing else than not having to be sent out to be blown up.
And I'm sure there are plenty of opportunistic Russian oligarchs and other people of actualized power that would be keen to take advantage of that, and any and all corruption that they can elicit from it.
There are certain circles within the United States that seem to believe that as well.
"It doesn't matter if a certain former president broke the law, so long as he keeps those evil leftists in their place"