Re: "when you contribute to an open-source project, [...] you're not going to get paid for that"
"Sure, and then go to live under a bridge alone (and be careful about trolls!), while Google, Amazon, Facebook & C. make billions out of your efforts... and it doesn't look they are making the world better, actually it looks they are making it worse."
While it's undoubtedly true that most 'cloud' companies were enabled by open source, there is a lot more to their businesses that just using some open source software.
It's kinda like saying that because you can machine parts, you are capable of building a car....
Fundamentally, it's not really about bits of code, but how they are integrated, managed, maintained and marketed. After you've figured all that out, you need to figure out how to make money.
For most large internet companies, the answer is not 'we sell code' but 'we sell eyeballs'.... Which is exactly why this whole discussion is kinda inane - Google et al are not selling code, they are selling access to people. Even AWS is not selling code, they are selling access to a blob of compute time/resources the details of which are irrelevant.