> I am making an argument that the principal justification for power of these individuals is the same.
You're drawing an analogy in the roughest possible terms. "A person can choose to become X", where X is a company or a lord, does not logically imply anything about the two things other than they are both choices. (Everything at some level is arguably a choice, so in fact this says nothing).
Similarly, "Doing thing X is risky" where X is starting a company or starting a gang, is not a logical argument for anything other than two random things are both "risky" (but perhaps in markedly different ways).
> Also, while there are small businesses in capitalism, yes, the core of it in practice are large businesses.
Roughly half of all employment, and the majority of employment gains, comes from small business. Roughly half of GDP comes from small business.
> And just like the lords, the owners of the large businesses are those who can either outsmart the other small owners, or just win the game of taking the risk.
In any competitive environment (be it sports, or selling widgets, or war) there are winners and losers depending on the preparation, skill, and execution of the players. "Football is war" is a metaphor, not a rigorous argument for why the Geneva Convention should apply to football.
> The fact that there is no direct violence in economic competition between companies doesn't invalidate the comparison I am making.
The fact that two things are meaningfully different in almost every sense does though. The only comparisons you've made are only in the most general metaphorical sense.
> The question why should somebody keep unlimited and indefinite control over something (be it company or state) just by virtue of organizing people around creation of that something still stands.
Besides the obvious point that no one has unlimited or indefinite control over anything, the tenants of private property are a well argued philosophical stomping ground. Why anyone should be able to own anything that they pay for... If they ever truly own it, if it is being taxed annually, or merely rented it from the State... If they should be able to keep it, or how much of it their family should be able to keep after they die... Whether a person can fully transfer title in something they create even if they are paid for it...
The fundamental reason that we let people own the things that they create or that they pay for is because that becomes the incentive for people to work hard to create great things, and because it's a way to give meaning to life. The fundamental reason that we don't take everything away from people the moment they die, but merely take just a large share of it, when it's over a certain amount, is roughly similar.
Other countries have tried to do it different ways, and IMO they have all turned out orders of magnitude worse for the wear.