And they will almost certainly have the biggest wrench. Before you consider the sheer difficulty of making mass violence happen (especially in a world where tech can be used to regulate a sufficient portion of people's worldviews as required), at some point they'll probably just have the upper hand militarily. As military tech gets better, wealth will be able to shift directly into physical power, amplifying their abilities against a comparatively powerless populace.
Difficulty: the "populace" is everywhere.
If you own everything, and you bomb the populace, you bomb your own stuff.
If everybody works for you, and you bomb the populace, you bomb your own serfs.
And those faceless individuals who are actually holding the weapons, and actually know how they work, and actually know, in a detailed, hands-on way, how to do coordinated violence with them? It turns out they're secretly members of the populace. You'd better make sure they think it's in their interest to keep using the weapons the way you want them to.
Yeah this is why the US fails everytime they try to keep "boots on the ground."
You can bomb people into oblivion but if you actually want to control them, most of the things that give superiority to a fixed group of rich are useless. Violence is still democratic if you're trying to get anything useful out of the people you seek to control. If you have 5 people and 3 of them are slaves with an AK-47 and a donkey, you have 0 slaves not 5 slaves.
Obviously the rich/powerful can't stay that way in a glass desert with no plebs to do their bidding, at least for now, so most of the technology the government and rich have are useless for subjecting a hostile populace.