Ok. So I write a speech for a politician, and it moves the world, and the world changes, and it becomes enshrined as the most influential speech in the history of the planet.
Then you write a speech, and it bores the audience who, in a fit of not understanding your motives, contemplates the lint in their navel.
We don't know from that alone that my speech was a better speech than yours was?
First, apologies for the double post. I promise to back away slowly from the keyboard...
The problem with the quoted argument is that at its far limit, you're equating popular with good. I don't have any time for people who put down the writers of thrillers, sci-fi, romance, but I also don't think John Grisham's latest is better than 'The Great Gatsby,' just because the Grisham is more popular.
Now I doubt you meant what you wrote to be carried to such an extreme. However, it's easy in this sort of argument to cross over from 'good, interesting writing is better than bad, dull writing' to 'the more people like a piece of writing, the better it is.' Once you get to a certain threshold of 'goodness,' the size of the audience matters less and other things matter more.