It seems like controlling these machines under a single entity would yield more profits.
Short term, maybe. However, once that is publicly known, it would kill bitcoin if they didn't
immediately distribute the machines to the general population. And if bitcoin died, they wouldn't be able to recoup the costs to make the ASICs to begin with since that requires a good bit of time. That is why you don't need to be too concerned about someone unfairly using ASICs for economic reasons. Non-economic, however...