I know exactly what you're talking about, another quote that reflects this is from Jim Jarmusch.
“Nothing is original. Steal from anywhere that resonates with inspiration or fuels your imagination. Devour old films, new films, music, books, paintings, photographs, poems, dreams, random conversations, architecture, bridges, street signs, trees, clouds, bodies of water, light and shadows. Select only things to steal from that speak directly to your soul. If you do this, your work (and theft) will be authentic.
But I would question his use of the word 'theft' and 'steal'. I get why he uses them, he's trying to be hard-hitting. But the reality is that just because you find inspiration from for e.g. Norse mythology does that mean Neil Gaiman's American Gods is theft? Is it fuck.
Inspiration borrows from the past indisputably. But American Gods as a work of fiction isn't just a recounting of the Norse mythologies.
I agree wholeheartedly with what you're saying:
Very few people come up with really original ideas that have never been there before.
and
First thing you learn in the creative industry: Take all those ideas and form and spin them until you can make them your own.
100% agree with both those statements. Any serious writer knows them to be true 👍