Parmandur
Book-Friend, he/him
This is not an attempt to say anything about the relative quality of Fifth Edition.
Law and Order, NCIS, and CSI are widely popular television shows that have a broad appeal. I think contending that their broad appeal means they are meaningfully better television shows than Breaking Bad or Sons of Anarchy would be a massive mistake. The opposite is also true. Popular things can be good, but they are not good because they are popular.
The same is true for Fifth Edition and say Exalted or Apocalypse World.
Your argument does have a major flaw, in the sense that quality isn't always the determining factor in what makes something popular, in fact lower quality items are often more popular because they're cheaper, advertised in such a way as to give the illusion of higher quality, or because they're associated with emotions that have little to do with the experience of actually using the product- ergo "Sex Sells" or the way certain brands entrench themselves in nostalgia for a time either long past, or that never was.
Often the shows that stay on the air the longest are the most "comfortable" ones, whereas shows that have higher quality and more ambition may find themselves abandoned by viewers uninterested in being challenged, but then those same ideas can succeed if only because a niche is being carved out by the ones that came before.
In short, popularity is suspect as a means of ascertaining quality.
Then again, 'quality' is also a meaningless word, because it refers to whatever virtues the person using it tends to value.
In terms of art, anything popular is possessed of a certain quality, qualities that appeal to a large number of people. Even if it is a base quality, like being comfortable or crudely funny.
Really, though,vn this extended analogy, 5E isn't CSI, it is Breaking Bad. Monopoly is CSI, Clue is Law & Order, and Settlers of Catan is Mad Men.
Other RPGs are Swedish Art Films.