Greg, greg, greg.
They have not put out any new music in 40 years. You are comparing them to a fast food chain that pumps out billions of dollars worth of processed garbage every day.
My point is, it all goes back to the music. That is the ever lasting presence of The Beatles.
Even now, Greg. There is a new wave of Beatlemania that is going to hit tomorrow once those CD's, Box Sets, and Videogames get released.
What else could you attribute that to? Popularity only works to a point. After that, it is all substance over style. And the Beatles are the most musically substantial group/performer in the last 45 years.
Some people may not want to admit this, because they can't look past the "mop top" days of the early British Invasion, but musically, especially their last 5 years, from Help! to Let it Be, you can't touch them. They did things in the studio, with 4 track recorders, that were considered almost impossible. But they did it.