Evaluation: money sources

Hey guys, i want kind of evaluate with what in the big internet marketing business people can make a living of their work. So far I have sold ebooks on amazon which was going ok, but as they closed my account I have to look for other opportunities. I don´t like just do something, what may take much time, just to realize that it is not a good path to go. That´s why I am asking you here now. I can say you what I think to know now:

- Very little people (in comparison to how many try) make any substantional money out of bloging
- For “normal” authors (who may not be very good in digital marketing) (at least in germany) it is very hard to make a living
- Affiliate marketing seems to work kind of … but here I have to explore more how exactly the successful people promote their affiliate links/ offers
- Building your own digital product, for example ebooks/ video courses seems to work also … perhaps even better then doing affiliate marketing


As I have sold my own ebooks already I like the idea to have my own product, that can be sold over and over again (more or less passive income), at the same time I am not dependent on affiliate marketing programs (if they stop or pay out money at all, etc.), so I am then kind of independent also.
What do you think, what is from your experience a good way to make money online (if possible passive)? thanks