I stand corrected. Perhaps my point (or my understanding) then is more subtle. Perhaps what I mean to say is that the GPL license comes with additional virility, not found in BSD et al.

Perhaps the difference is most noticeable in libraries (where I do most of my work). Using a GPL library in a commercial app is generally impossible, where BSD (or LGPL) etc is completely acceptable.

In my experience companies are allergic to GPL specifically, whereas other licenses - especially MIT and BSD are far more palatable, and are frequently used.

That is really my point. They will use and celebrate your code if they can use it to make money and give nothing back. If you place some restriction on it that forces openness then it becomes toxic waste to them. It is a one way street.