Total nonsense. Before all this advertising nonsense, the web used to be literally full of people who had enough intrinsic motivation to create without compensation. People used to literally pay to have their own website in order to get their ideas out there.

Open source is literally proof of this. I make software in my free time simply because I enjoy it. I publish it out there in a variety of licenses with zero expectations. I got a GitHub Sponsors profile with zero sponsors and I'm not even mad about it.