Great point. It seems obvious in retrospect, yet I had never thought of it with that level of clarity. It also explains why, as I ponder my career, I'm drawn to companies where a significant portion (or all) of my work would be open source.
On the other hand, given the terrible outcomes communism produced in the 20th century, it has a well-deserved bad reputation. I'd therefore hesitate to link it to open source without noting why open source is different: Code, once written, can be copied infinitely for free (or at a very low cost), so the model can work.