Think about it this way: When Linus started working on Linux and decided to release it under the GPL, was it because he wanted companies to use it as the basis of billion-dollar revenues without sponsoring development or compensating him for his work? Lots of people start contributing to open source at a smaller scale, where it's just individuals and small businesses and non-profit orgs sharing with each other, but it becomes kind of a different matter when a company has dozens or hundreds of millions to throw around and doesn't share back. At least in the case of Linux it is well-funded now but there are other cases where core infra has still suffered - you can find recent stories about how the maintainer of NTP struggled to pay rent even though massive companies rely on it.