Comment by _greim_

It isn't so much that companies are unfairly using others' work. It's that if you're going to use an open source tool in your business's codebase, you'll inevitably need support, upgrades, and bug-fixes, which translates into you putting pressure on the maintainers to do more work. By all means, use those people's previous work to put something amazing out into the world quickly. However, when you inevitably need help, be prepared to either: 1) Have people on staff ready and capable of contributing to the project in non-trivial ways; 2) be willing to either hire or pay the maintainer(s) market value for their time, just like with actual employees.