Every system can be captured by wealthy interests. Markets are not unique there. Once in a rare while someone not wealthy captures a system - but they inevitably use that capture to become wealthy so it doesn't really matter.

Classical liberalism is the least likely for that to happen to, but it has happened there too over and over in history as well. I still support classical liberalism, which is not the same as supporting the market even though classical liberalism ends up being a market.