I can appreciate your viewpoint, but it is a well-worn one which I have heard for well over 10 years now.
The prediction of the MS collapse is as popular as the doomsday myth.
The problem with open source is how to set standards and how to sustain these in an economy that depends on revenue. The adage that "you pay peanuts, you get monkeys" is especially true, resulting in the demise of all those socialist societies at the end of the last century.
I am pro MS, but I am also interested in the goings on of the open source community.  I also develop in Java and like many others have investigated Linux, PHP, and all the rest.  But for everyday use, it's Windows all the way.  That's the key to the Microsoft success.  They have the secure market penetration, they have the image.  It has become a mindset as anyone who has tried to push Linux onto a non-geek will know.
As for your sustainability analysis, well maybe you could check back with Bill in about 10-15 years time.  You might just be able to say "I told you so" ...