I don't really disagree...except that fulfilling "potential software success" isn't the point of the GPL. The point of the GPL is to propagate Stallman's "Four

I don't really disagree...except that fulfilling "potential software success" isn't the point of the GPL. The point of the GPL is to propagate Stallman's "Four Freedoms", and anything/everything else really is tangential to the issue. Whether or not the license has held back companies, or individual developers, or the evolution of software development as a whole isn't really the primary concern of those who use or support the use of the GPL. From that perspective, what you refer to as "the downsides of the GPL" really aren't downsides, any more than an apple being green instead of red is a "downside". The point of the apple is to be eaten; colour is more or less irrelevant. The point of the GPL is to make certain a specific ethical belief is followed and transmitted; whether that ideology is convenient or not for others is secondary at best. Calling the license a "failure" from a viewpoint completely different than the one it was created by is trivial and meaningless, in the same way that it is both trivial and meaningless for me to call someone's apple tree a failure for not growing the colour of apples that I happen to like.