@arafiq What is a giant killer, and what dac or dacs are the giants? I'd call something like Wadax Reference dac a giant, but dacs in realm of $10k doubful. Pricing of audio components is partly a function of business model. Where the component is designed, manufactured, marketing budget, distributor/dealer network or direct sales, profit margins. Its possible a $10k component actual manufacturing cost could be very close to another component that retails for much less. In this case the higher price component is not a giant, therefore, the lower price unit is not in fact a giant killer.
While I'd generally agree price correlates to quality in audio realm, there are enough products and logical reasons why this may not always hold true. Purchasing products based purely on price is rather like confirmation bias in regard to faulty posits.
Bottom line, direct comparison between two components in the exact same system, preferably one's own, is most valid estimation of a components relative value. Many long term reviews over long period of time in many different systems holds value as well. Price alone, at least without factoring in business models is not very good indicator of value.