The real question is simply whether this is the best methodology for society or if there is a better system for all. Oligopolies reduce competition and facilitate artificially high prices along with making it easier to short change workers. Greater competition in every industry may help
Sure, that's a real and serious question... that is totally undermined by describing de facto market collusion and political scale-fixing and plain old fashioned legal greed as "theft" because they very materially aren't theft. If you can prove theft you can prosecute it, after all.
this is, categorically, a semantics debate. you are describing a very narrow definition of the word where an individual also has the option to starve to death instead of mowing a lawn. if that is the only definition of the word that you are willing to subscribe to then this is all a waste of breath
At that low-level angle it isn't. But if such trust conglomerate is enforced and shielded from equity law enforcement, from competiton or dismantlng, by abuse of executive position in exchange for support offered by trustees, it's a form of embezzlement, which is a theft.
If you had government that was interested in representing its voters, they would stop the concentration of businesses into fewer, larger enterprises, these only benefit those rich enough to invest in them, everyone else just gets exploited by them.