Unfortunately what is also true is that some very expensive/overhyped DACs may not sound good and some very cheap/underrated DACs may sound great! How to know if something sounds good and is not overhyped/sponsored good? This becomes very complicated. Sounding good to some may not sound good to others. Its very subjective. Something sounding very airy, dark or purple may not convey to others what is meant here.
That way, measurements terms like SINAD are very well quantified but may not convey how the DAC would sound like?
The gap, to start with, I think is due to lack of quantified definition of subjective terms like warm, dark, airy etc.