If Microsoft took the source code to Nano and made a Nano+ that reads word files or something, closed-source, selling it for big bucks, etc, the value of what they're offering cannot possibly be more than the delta from what is freely and openly available. They didn't make the original any less available, and a user is only possibly going to pay if the features are different enough to merit the cost over the freely available version. Similarly, if Amazon has a product based on an open source product, what they charge can only possibly be for the values that they've brought to it. They haven't stolen anything.
A lot of GPL advocacy seems to be based in sour grapes and it's offputting.