I would encourage you to read von Mises, Hayek, and Rand. They make a compelling argument that monopolies form in mixed economies in relative proportion to state interference - especially subsidies. As long as companies can lobby the government for more regulations and “safety controls” to raise barriers to entry, monopolies will exist.
Regulation promotes competition? What kind of nonsense is this? Regulation is always a form of interference, that is simply the nature of regulation. A more plausible (but still wrong) argument would be that regulation interferes with competition to induce a positive outcome for one competitor, and a less positive outcome for another.