you don't suppose the danger of the market for medicine in the US prior to the 20th century had anything to do with the fact that
chemistry didn't exist as a discipline? Just what do you expect them to have regulated?
The free market is quite good at providing consumers information, but often only if the consumers demand it. For a few decades now, consumers have gradually become more ethical in their consumption choices, and the markets are reflecting that. It's a long road and there are certainly many, many places where things can be improved. By contrast, consider that there is a lot of demand for certain values, like transparency, honesty, not sexually harassing your underlings, in government, and exactly how responsive do you suppose it's been?
The faulty assumption is that government will somehow be 'the betters' of the general public. But every indication of the narcissistic type that gets elected, and the petty bureaucratic authoritarian that is unelected, suggests that those advancement in government may not necessarily select for those traits you want. Neither does capitalism (as it's structured today), but at least consumers have a direct option to opt-out of unethical things done with their money, which they do not for government.
To pick another "fundamental", why do you suppose lightbulbs don't explode, and various and sundry electrical equipment doesn't electrocute you in the US? It's because regulation is being done by a private, nonprofit entity (the underwriter's laboratories) which goes through and certifies equipment for consumption. A good example of the free market working quite well to ensure safety, beyond even what the consumer might expect, with far less government interference.