It's surprising in light of the prevailing idea that markets enforce competition towards the lowest price. This idea forms the basis of the claim that market-driven healthcare benefits consumers by lowering costs.
It applies to almost all real-life markets. It's so standard that we don't even notice it happening, and focus on the exceptions. There is no level of economics you can reach where "competition drives down prices" stops being taken seriously; Nobel-winning left-wing economists like Stiglitz and Krugman accept that as true and relevant. So does Marx(!), who focuses on how lower costs are achieved at the expense of workers rather than capital holders.
Restaurants run at effectively zero margin. Lawn chairs and pencils and window blinds sell for essentially the cost of manufacturing and distribution. Even complex services like VOIP calling have moved from high profitable industries to "essentially free". Markets aren't inherently noble any more than they're inherently evil, but a major part of their value is that price-fixing hardly ever works.
Without appreciating that, we lose sight of just how strange healthcare (and college, and housing) are. When prices stay far above costs despite what presents itself as competition, there's something significant happening that deserves more attention.