Not true. Just see MySQL for one example. Before Oracle bought MySQL AB (for $1 billion) their revenues on commercial support for their largely GPLv2 software was in the tens of millions. The same may already be true for Monty Program AB who provide commercial support for MariaDB. The closer you get to infrastructure, the more being open source is a competitive advantage.
This is not the case with most open source software.
Actually the majority of corporations are leechers, using it as "free beer", only paying back if they really have to, as many corporations don't use software without support contracts.
Or happen to have some FOSS followers taking business decisions.
Otherwise, I can tell you from my experience working on Fortune 500 consulting projects, very seldom is any money or contribution given back.