the bad bad comercial guys ;-). do you really think you can make money with a comercial license? in the case of flext i doubt it. let them pay for your support and your knowledge and don't ignore the advantages of the LGPL in some cases: Apple was able to use the KHTML library (HTML rendering) for there closed source Safari browser, because it's licensed under the LGPL. They made a lot of improvements to KHTML, which means a better open source HTML browser for Linux. Win-win situation...
Of course, nobody would expect to earn (a lot of) money selling flext licenses. But it's a matter of principle. There are Max/MSP packages which are commercial (tap.tools, litter power etc.) and there will be more, possibly even for pd. I developed flext for my own (musical) projects in the first case and it has become larger and more time-consuming than i intended. I'm extremely happy that other people use flext but i'm not in the position to finance some else's commercial developments.
so, summing up, open-source rules! best greetings, Thomas