Or one could argue based on that, the marketable choice. If you ask a Conservatory student the entirety of important music is ten people from over three hundred years ago. I think anyone who honestly says that 1960s music is that much better than all other pop/rock music just hasn't taken the time to fully explore all the niches that are around now. Also I would argue there is major Canon Bias, especially for music writers. Yes, good music was centralized, popular, and playing on the radio in the late 60s, and since then popular music has gotten safer and more polished and good music has splintered into a thousand niches and subcultures. So 1960s is the music that's easiest to agree on. But it's not unquestionably the greatest decade, just the decade where discovering the best music requires the least work. The de-facto Rock Canon we have now is no different from the Classical Canon. Not entirely inaccurate, but not complete, and causes a lot of bias and summary dismissal against anything not on the list.