And nobody in power is going to allow you to organize to any real extent before interseding. They force you to play with their rules to get in the game. The only away around it is to already be a well known and publically liked figure that people will rally behind.
> What keeps the guards from taking all the profit?
You shouldn't kill the goose that lays the golden eggs. Let the merchant do the merchanting and make the profits and you hang out and get your paid vacation.
If you take all the profits, the merchant won't stay in the business and then you don't have a client.
There were legal system and courts well before 1000 years ago.
It does not really stop assassinations, but it lets the rest of us get on with life without worrying when a thug will take our stuff.
Take a simplified model of a king, a bunch of nobles, beneath whom are a bunch of knights, beneath whom are a bunch of serfs. Collectively, the nobles control more power than than the king. But if an individual noble defects while the others remain loyal, then the King maintains enough power to crush the uprising. So as the King, you have to proactively maintain a status quo where the nobles can't easily collectively plot against you. Classic strategies include maintaining some kind of nebulous ranking, where nobles are constantly competing with each other to garner favor, and thus likely have more to gain outing a rival noble's conspiracy than joining it, keeping the nobles sufficiently comfortable such that the risk of losing that comfort acts as friction against plotting against you, and in times of extreme distrust, keeping the nobles close at hand such that you can take decisive action against the individual noble before the forces they control can show up.
At each level of the hierarchy, recursively apply similar strategies. Nobels need to keep control of their knights, knights need to keep control of their peasants.
The first reason it’s not more common is that wealth isn’t so static. Landlords have to collect rents, oligarchs have to skim off the top of their corrupt enterprises etc. A guard who kills the landlord, then manages to organize rent collection for the benefit of other guards, has essentially become the new landlord.
The second reason is that a guard doesn’t just have to kill the landlord, a guard potentially has to kill all the other guards who want all the landlord’s wealth for themselves.
Since rent has to be collected anyway, and an individual guard has a low chance of surviving against all other guards, remaining a guard is a lower risk option.
This does happen but yes obviously attempts are made to prevent it, the guards my not be familiar with the journey, other guards may be family members or trusted friends. Often then the guards become the Merchant then.
You see this with the billionaires building luxury apocalypse bunkers in New Zealand and other exotic locales that are like mini theme parks. It slowly dawns on them that when society breaks down that's exactly what it means. You can't depend on normal social norms or laws anymore, how do you stop your security team from kicking you out of your own bunker, how you do you charter a flight to your bunker? It's a problem with no guaranteed solution.
Prepping is different as it doesn't involve depending on others. Just yourself and your preparations.
You can bet they're considering AI killbots as a possible "solution" to the "hostile bodyguard" problem...
However once they killed the "elite" or "oppressor" they couldn't stop the killing, and kept redefining who the "oppressor" was, until it was anyone who had one more cow than the rest.
Read Leviathan: https://en.wikipedia.org/wiki/Leviathan_(Hobbes_book)