I'm over 20, and I've never heard of the author, group, song, or movie.

For another data point, I know plenty of people who had never heard of The Princess Bride, Firefly or Monty Python before me telling them.

There is no level of popularity which ensures universal familiarity. You should always assume ignorance is genuine. See also: http://xkcd.com/1053/

Agreed. I tell people: If my mom knows about it, it is probably famous. If not, it's a niche audience ;-)

What? Why would you even consider that people were trying to be flippant (disrespectful?)? So what if people know or don't know the artist? Does its popularity demand some kind of instant respect for the authors argument?

I'm just confused by what you are trying to achieve with this post

Because a lot of the earlier comments seemed to think this guy was some disgruntled starving artist who had a million Pandora plays but no real success.