The assumption is that price is supposed to reflect quality. Unfortunately as you say, too often price is a weak signal. And price often signals current fads/fashions rather than quality.

Non-monetary costs are often a better indicator because good quality does cost you more: more time, more expertise, more judgement, more homework.

Plus we usually have narrow needs, which are hard to match. Price reflects a single average market scale, not how a product/service fits our individual conditions.

Finding the right compromises is hard work.