It's not that they made more money from merchandise, it's that they sold more t-shirts than albums. Implying that more people were interested in the "image" of punk rock than the music.

I guess that's the definition of 'iconic' - many a time I have approached someone wearing a Ramones or Motörhead T-shirt trying to chat a bit, only to be told 'Sorry, don't know the music at all, but the shirt is cool...'

Gabba gabba hey!

I can wear out a t-shirt much faster than an album, tape or CD, and I am not very caring of the conditions of albums.

I've also never seen anyone slam dance carrying a Ramones album, but I have seen them slam dance wearing a Ramones t-shirt that got tore up.