If anything, they have explicitly enforced monopolies time and again. The medical industry within the US (and abroad thanks to other governments) is an infamous oligopoly with little to no competition (leading to inflated prices). Then there's the US Postal Service and the American Letter Mail Company which was explicitly outlawed because it was so thoroughly outperforming the USPS for a fraction of the cost.
And in fact, when income taxes and the sort are in play, there's little incentive to actually break up any sort of monopoly or oligopoly. Think about it: It's guaranteed income with lesser chances of failing. It's steady and reliable income for the state. And that doesn't even touch the money laundering that is lobbying.
If anything, they have explicitly enforced monopolies time and again. The medical industry within the US (and abroad thanks to other governments) is an infamous oligopoly with little to no competition (leading to inflated prices). Then there's the US Postal Service and the American Letter Mail Company which was explicitly outlawed because it was so thoroughly outperforming the USPS for a fraction of the cost.
And in fact, when income taxes and the sort are in play, there's little incentive to actually break up any sort of monopoly or oligopoly. Think about it: It's guaranteed income with lesser chances of failing. It's steady and reliable income for the state. And that doesn't even touch the money laundering that is lobbying.