Yeah I ran into this yesterday, because people keep throwing the "5e is the greatest game ever because so many people play it".
Argumentum ad populum - Wikipedia
en.wikipedia.org
But every time I come up with an example of something that was popular but not very good, I get told "it's not the same thing" so I decided to just accept that people like what they like and move on before they start saying "maybe if you don't like it, you don't belong here".
We've had close to a decade of every year seeing double digit growth, even though there are plenty of alternatives. That growth is what tells me that it's a quality product.