Erk. The GPL is a scary beast. In my opinion; its very existance scares software developers out of working on Linux products over Windows products. On Windows; it's pretty safe to assume that it's going to be alright to release a product that relies on the existance of a wealth of useful components that are bundled with the operating system as a 'closed source' product for whatever reason.
On Linux; you have to check each linked library to make sure it's LGPL'ed rather than GPL'ed. Apparently; the act of dynamically linking to a library constitutes as a 'derivative work'. So GPLed libraries cannot be dynamically linked against unless a linking project is made open source itself. ( hence a L(esser)GPL for certain libraries, that explicitly discounts linking as derivition ).
Whatever Microsoft's 'ills' may be; they certainly make a better provision for developers; in terms of development products / libraries and legal permissions to use libraries and components. I can be open or closed source on a Windows project, at my own chosing; and get alot out of Windows as a platform, almost to the point that it's made easy for me; by Microsoft and fellow developers alike. On a Linux project, I have to be a bit carefull; lest I be 'forced open' by a few lines that assume a user has libcoolutility1.so; or rewrite libcoolutility's functionality myself.
As a developer, if I see the words 'open source'; I see code or a library made available to the general public for whatever use the public pleases without any usage restrictions. GPL'ed code isn't open source in my eyes; because it comes with a restrictive copyright, sorry, "copyleft" agreement. I guess the GNU would term my ideal 'free source', but I've never noticed them rant about the drawbacks of that.
I wouldn't feel any warm fuzzy feeling from upholding the GNU/GPL's ideals. I just see it as a way of legally protecting source code, and letting me see what others do with that code, thus NOT letting them use that code freely. If you want a warm fuzzy feeling; try the 'AGPL' on your next open-source project; that is, the one-clause 'Anti-Gnu Public License'.
'This source code, and any constituent part of this code, may be released in any form, modified or otherwise, under any licence except any version of the GNU General Public Licence; and providing that this clause is a clause of such a qualifying licence'.
Open source doesn't mean lower priced either, all it implies is that source code for a given product is available to customers in some way; of course, if a customer distributes source code, it's their perogative, but unless we're talking about true consumers, it's not good to help out the competition, in any way.
Big, comercial open-source products generally aren't cheap. They rely to an extent on one-or-more of; expensive support, being so specialized that uncontrolled redistribution isn't a major issue, or having usage licences ( It doesn't matter if a product is open source, if the target consumer can't use it without a licence, and isn't likely to go looking for a way to disable licensing and release their own version ).
There is, at least one good market for open source code, GPL'ed or otherwise. That is, enourmas internal business/management/technical applications; where the target 'buyer' has a development team wanting a base application to modify for the company's specific needs. In that case, there's no real cause for a 'revise and release' situation; but if a development team wants a base application for a commercial product for general release; they aren't going to want a GPL'ed base application, unless it's something REALLY special.
So. I guess; I don't see the GPL as of being any use to anyone. Yes; it protects the Linux source code; potentially meaning some big private investors in development are turned off to the idea of working (at cost) on Linux or even Linux software. Yes; it means I can release the life-consuming applicationX proud in the knowledge that someone can add one extra feature, price it for less, spend more on advertising, and release it without even mentioning the code's original author; and Yes; it's an amusing twist to copyright law; that isn't anymore or less restrictive than 'you may not reproduce this source code commercially'.
Anything intentionally GPL'ed could just as easily have been released with a passive licence; and it would be just as 'open'. Overall though, I'd rather have good closed source dynamic libraries and products, than half-baked open source ones that I'm expected to fix with 'help from the community'.
As a personal consumer; just EXPECTING quality, original, cutting-edge software to be cheap is a problem. Production is a costly process. I'm not gonna use Windows as an example here; lets think about, 3D animation software, audio development software, high-quality graphics and simulation software : if it's not expensive, there's going to be something wrong with it.