So? How do you know they wouldn't be even better with proper studio monitors? Or produced faster.There are literally tens of thousands of great-sounding reference tracks mixed on loudspeakers that would never score highly in objective measurements
Who says they are "best sounding?" Based on what comparison in what controlled testing?. There you have your metrics, and those tracks are most likely among your favorite best-sounding audio productions you have ever heard in your life.
That is not why they are, i.e. the speakers. You have no idea or testing as to what role those speakers played or didn't play in such mixes.And do you want to know why that is? It's because those loudspeakers just happened to work great for those audio engineers mixing those songs.
This is all bunch of suppositions, never put to testing in a controlled environment to determine the role of the monitors used. This makes what you claim folklore.