With respect, what is a functional market, and why does such a market require that consumers be vigilant and make good choices?
If consumers make bad choices, don't they eventually learn to make better choices?
If consumers make bad choices, don't they eventually learn to make better choices?
Even if we assume that consumers will learn to make good choices, that would require that they understand their choice was a bad one.
This is an A-B-C problem (antecedent + behavior => consequence). The consumer must first recognize that a negative consequence has occurred, and then determine whether it was their behavior that was flawed (they made the wrong choice) or a flawed antecedent to that behavior (they'd made the right choice, had their assumed knowledge of the situation been accurate).
Consumers don't do this though. Studies have repeatedly proved this (e.g. the very large effect of marketing and advertising on selection of products of otherwise equal quality).
Consumers may make decisions that are non-harmful (i.e. they got about the same result but simply paid more) but they certainly do not make decisions that are optimal.
In the healthcare "market", they don't.