- if you want to provide something valuable you need a good idea, some skills and hundreds or even thousands of hours of work on your idea
- all that work on creating and maintaining your project makes the potential income not passive at all
My impression is that the people who succeed at this usually start with a good idea, work on it for a while and somewhere down the line potentially turn it into an income stream. But the interesting idea comes first. On the other hand, the people who begin with the goal of making money and just the wish to "have passive income" or "be an entrepreneur" usually don't get anywhere. Unless they scam people or happen to get lucky, of course.
Also, everything from Robert Kiyosaki including "Rich Dad, Poor Dad" is somewhere on the scale between questionable advice and scam.