The world is incomparably better than pre-capitalism. Yes, the healthcare system in the USA sucks. Doesn’t invalidate the rest of the thing.
It does, though. Same shit can be seen everywhere. Food for profit? Addictive poison. Health for profit? Ineffective care with prolonged suffering and excluded populace. Cars for profit? Emission cheating, subscriptions. Farm equipment for profit? War on independent repair.
Profit motive worked when the market was regulated, there were not many monopolies, excessive profits were progressively taxed, research has been sufficiently well funded, worst jobs were outsourced to colonies and most importantly markets were not saturated and there was an organic demand for new and better products.
Decent description below: https://www.investopedia.com/terms/m/marketfailure.asp
1) Information asymmetry. Patients do not generally know how to select and shop for their treatment without medical expertise.
2) Adverse selection. Unhealthy people want good healthcare, which drives up the risk pool of "good plans". While insurance companies in general want healthier patients, which often leads to insurance firms to compete to offer plans that only appeal to the healthiest people. (I.e who can offer the most restrictive, and cheapest plans) see insurance death spiral. https://en.m.wikipedia.org/wiki/Death_spiral_(insurance)
3) Perverse incentives. Profitable treatment does not always align with best treatment decisions. This both comes from providers and insurers. See information asymmetry.
4) Monopolistic characteristics: A Monopoly is generally defined by a firms ability to restrict output to reach the profit maximizing production (absent of meaningful competition). Try seeing a specialist on an HMO and you can figure the relation to healthcare. Significant regulatory and market capture makes avoiding with health insurance impossible (including your providers insurance), leading to spiraling costs.
The issue at stake isn't healthy profit-seeking that happens in a regulated market - but the rent-seeking that occurs when markets break down (logical endgame of capitalism).