Regulatory intervention into a marketplace is not "ensuring vigorous competition."
Markets are vigorously competitive in their natural state. This is the nature of a market, where firms compete for customers' business. This can only be hindered with regulatory interference where a legislator is arbitrarily granting privileges to certain firms and not others. That's crony capitalism or mercantilism. It's not a free market.
Free markets don't exist without governments. They don't have a natural state. A government is a monopoly on force that enforces property rights and contracts. If there was no government then you would have no market incentive to do anything because you would have no protection from theft or breach of contract. The contours of what you can own as property and what you can enforce in a contract are necessarily defined by the government.
The problem with idealized free markets is that "free" is not the natural state of a market. You can act as a de facto government by having a monopoly on something other than force (like land or infrastructure), and de facto government actions have all the same defects as de jure government actions, generally with none of the public accountability.
Markets are vigorously competitive in their natural state. This is the nature of a market, where firms compete for customers' business. This can only be hindered with regulatory interference where a legislator is arbitrarily granting privileges to certain firms and not others. That's crony capitalism or mercantilism. It's not a free market.