Except those "monopolies" ship freight at drastically lower prices than their European counterparts.
US rail has it's problems but freight rail is not one of them.
4/5th of EU rail traffic is passenger trains which changes a great deal about how each system operates. The EU actually has more track miles per person than the US and vastly more electrified lines, they even pay less for rail infrastructure projects etc, but freight traffic very much plays second fiddle.
The US on the other hand allows for much heavier and slower freight trains. It’s very good at moving heavy stable bulk loads like coal and corn, but less so about moving perishable goods. US freight trips to Mexico can take as long as 45-60 days.
(Short version - each of the major U.S. freight RR's is more-or-less a monopoly in the part of the U.S. which it serves. If management relentlessly optimizes for profitability, and doesn't much care about customer service, shipping delays, sustainable staffing levels, etc... Well, I'm sure RR management has enjoyed some fat profit-sharing bonus checks.)