Thanks for your kind reply. Since you seem to be a sensible person to discuss with here are my points.
First of all, I asked for a proof that people are migrating from Windows to other platforms. You either didn't or couldn't give any. Stating that it is well acknowledged doesn't say anything. It just means that either knowingly or without knowing you repeat the same lie or an assumption that is not true. That's usually the motivation behind so many number of anti-Microsoft bashing. I like open source and support it, but I find it outrageous to make up lies and accusations against Microsoft, and over the long run it is going to hurt open source very badly.
Related with the above issue, my point is that, your own argument for some reason apply only to Apple. If one should make a point that open source is good with commercial applications, then his/her argument should apply equally to windows and Microsoft. You simply omit windows here, and focus on Apple, which hurts your own arguments, because that is simply not honest. If you were honest, you would make one single argument and apply it to all commercial applications out there, not just Apple itself.
"solutions that are at the same time polished and free -- as in "not proprietary"."
How come Aqua on Darwin along with iTunes, iDVD, and so on are not proprietary? If you have proprietary program in your solution, your solution can not be free. You can't have both at the same time. You can argue it is the best if you mix them, but please don't say that by mixing them you still have free solutions.
I don't believe that Apple is helping open source community and sees a trend here. Apple is helping open source, because 1) the licensing requires them to 2) they want the help of developers to fix bugs etc.. in their core os code or server programs. This doesn't look like a general trend, this looks more like a company takind advantage of certain things going around them, which is clever and right thing to do so for the company itself. By the nature of the things it is also good for the open source. But open source doesn't need more improvements to the kernel, servers, etc... we need more improvements at the user level apps, like KDE, Gnome, Office, iTunes, iVideo, iChat, etc.. and the only thing that Apple is doing at that space for open source community is KHTML and that's because of the license. You can't expect Adobe to open source its photoshop, or contribute to gimp, can you?
Another issue is that, if you tell people it is best to use open source with Apple's products, then you automatically limit the improvements in the open source user space applications. That means an end to the dream of a usable open source desktop. I don't care whether you support open source or not, but that argument is not good for open source. My initial point was that, you don't apply your argument to every os vendor out there, second as a supporter for the open source, I believe that open source shouldn't give up the hope of building a true open source desktop. I see that this will hurt Apple, and that's why you may be trying to convince us that server and os stuff for open source is enough.