[cookiecaper]

Your analogy stops short. There's no reason there can't be entrants besides "Sony Bread Co.". As long as the price is below market rates, there is an opportunity waiting to be seized, and someone will come along and seize it, at which point the cartel previously described will be forced to follow suit and pay full market value or lose all of their employees.

It could even be argued that the trust-busters in your analogy are really just anti-entrepreneurial and are attempting to close a rare market opportunity to protect the extant oligopoly. Many laws and regulations actually are written by the dominant powers in a field specifically to heighten the barrier to entry and prevent innovative new services from presenting a threat by burying them in paperwork and compliance expenses.