Then why do they literally pay millions of dollars for the music catalogs of top acts. And just try to use a classic rock song in your movie soundtrack, that will be cost you a lot as well.
Main reason “The Wonder Years” reruns can’t be found. Similarly SCTV’s music parodies.
The fact that movie makers and ad execs are buying and using songs that are decades old just confirms the point. With a few exceptions, movie people don't know or bother with more recent acts. Put a song from the 60s, 70s or 80s into your movie, and most of the appeal is nostalgia or the comfortable recognition of what we already are familiar with. When they put Beatles or Stones or Simon & Garfunkel tunes into movies 50 years ago it was a sign of life in both music and film. We don't have that now.
Because it’s not actually that much money. Remember most of these labels forking over fat cash for these catalogs are also movie studios. Compared to a superhero movie budget they’re paying bupkis for these back catalogs.