alt Hacker NewsI don't know if I have a good argument for it myself. I have seen a lot of people saying specifically that they based their {thing} on {prior thing} rather than something from life, but I haven't exactly kept a list. Beyond that it's mostly a feeling.
To give an extreme example, just to make what I'm talking about obvious, this recent Instacart superbowl ad comes to mind: https://www.youtube.com/watch?v=fXGTaGjqERc
Nothing about the scene or anyone in it is really connected to any reality; the whole thing is like a second-level simulation of prior media.
Your observation reminds me of this book, Simulcra and Simulation
https://en.wikipedia.org/wiki/Simulacra_and_Simulation
The very brief (and bastardised) summary is that we're cutting ourselves from what is real, so we base our art on the fake reality that we're experiencing.
I'll never forget when one of my teachers asked: "who has seen a sheep?" The entire class put up their hand. The next question was "who has seen a live sheep, in front of them?" more than half the class put their hand down. We all know what a sheep looks like, but not because we've been near one.