The post-apocalyptic stable-state doesn't require a billionaire at the top; without the threat of state violence, I posit that the most stable configuration is the people who control the guns calling the shots. Things will get feudal fast medieval-era food tasters included; explosive collars do nothing against the chef intentionally lacing food with botulism neurotoxins from canned food.

> [...] with security team to have enough incentives to not challenge leader and enjoy what they have.

This is what we have with the current system, underpinned by the "rule of law" - which has seen better days tbh. These billionaires have been cynically chipping away at its foundations without realizing if society falls, they fall with it. In the dystopian fantasy, the nerds in charge have to pacify all their employees all the time, an ambitious or dissatisfied lackey only needs to get lucky once.