The GPL promotes one type of "open" source model.
Exactly. I love the idea of GPL and am glad it exists. I use GPL software whenever possible. This post however, is not about the merits of GPL, but to drive home this point: it's difficult (not impossible, but difficult) to make a living by relying on GPL software. Finding a "balance" between the GPL model and complete closure is something worth pursuing. It's not like GPL couldn't still be used by those who wanted to use it.
The GPL is simply not for every developer. It does not allow for trade sectrets, and trade secrets are legally protected for a legitimate reason: the opportunity to be rewarded for innovation. Without it, there would be *less* incentive to invent and innovate.
Clearly, some are willing to invent and develop technology without this protection, but many such as Microsoft, Adobe, Oracle, the average person with a Computer Science degree, will demand some of this protection when they really want to earn a living from their software.
As someone who's worked for software companies, it's hard to imagine those companies GPLing their products, and easy to imagine the company losing half its profits or going under altogether if any company with an IT department could legally recompile the source code and use the software without payment.
After all, companies do have the right to act in their own self-interest, even if you feel they are misguided.
To invent, you need a good imagination and a pile of junk. -- Thomas Edison