As we’ve pointed out around here many times, capitalism is a description of a method of ownership, markets of a method of exchange.
And between the two markets are vastly more important than capitalism or capitalists. For it’s the markets which encourage the competition, not the capitalism.
Here it’s mostly a semantic argument: but in the larger world it’s a very important distinction to make. Capitalism and capitalists will, where they can, shut down competition to the detriment of the consumer. Which is why we’re so enamoured of markets which create and maintain the competition to keep the capitalists in line.
This is why your humble Devil doesn't like state-owned monopolies: because they try to remove the really beneficial part of the equation—the markets.
This goes equally, of course, for governments artificially shutting down private markets—usually after lots of lobbying by big businesses—through massive amounts of regulation or through the granting of effective monopolies over such things as infrastructure. Or currency.
That companies attempt to get governments to do this is hardly unsurprising—as Tim points out. But the best way to stop them doing so is to ensure that politicians do not have the means to do it. To paraphrase P J O'Rourke, when legislators decide what can be bought and sold the first thing to be bought and sold will be the legislators.
As such, ensuring that the legislators can do no such thing is the sensible thing to do—but this is, alas, also something that we have not yet worked out how to do effectively...