People make money off of Linux, not because they control the intellectual property, but because they bought Redhat stock, or they provide service and support built around Linux. What you see here is a pattern. No one is feeding their families with the intellectual property, so if it's open, no one gets hurt. Now, sometimes they're right. And sometimes they're not.
Some software companies make their money by protecting their intellectual property.
For example, Cadence . Cadence make tools for electrical and computer engineers. The only thing that you really need to know is that the licenses cost thousands of dollars because the algorithms took millions of dollars to develop, and they are the only things that differentiates Cadence products from anyone else. They wouldn't make money just providing support, and if they GPL'ed their tools, they'd file for Chapter 11 in a couple of months. At this point, you've already started your flames, and I sense I need a better example.