Blame the instructors. I was an art student at UW-M (Milwaukee) in the late 60’s. That sort of stuff was enthused over and encouraged. The very worst crit you could get from an art teacher/professor was “It’ll sell.”
Today, I hear, “Well, you actually made a living at it!” (depends on what you call ‘a living’), from some of those very same students, most whom didn’t continue in art, but didn’t end up destitute, either.
I remember when they re-named Commercial Art something like Advertising Design. People would get agitated if you said you did ‘commercial art.’ ‘Commercial’ became a dirty word.