[Kinanizer]

Of course windows will go down, but Google's just going to take its place. I think it's all just part of the life cycle of a bushiness:
Great idea, go big, make tons of money
Become large, bloated, and expensive
Get beaten out but by smaller, cheaper, better quality competition

What makes you think Google won't bust too then, based off that logic?

Of course it will, it just hasn't gotten to the "bloated" stage yet, and I'm not sure what the company to replace Google will be.

But Google is worth more then Microsoft as is...
How is that "smaller, cheaper, better quality competition"?

You can't compare the worth of Microsoft to any company. Their stock is constantly between 20-30 points, while Apple's is 450+ points. The reason for that is most of Microsoft isn't in the public market, and therefor you can't accurately compare worth. But just to give you a comparison anyways, Google is currently at 723 points, and the lowest they've been in the last year is 559.