Well i suspect it is just because it comes with new computers and not many are gonna throw it away for someting else.
I have three computers running it for that reason. But, it still frustrates me that it will not let me share everything.
Sharing is very easy in Win7. Are you running Pro or Home ? Are all machines in your HomeGroup ? I am able to share data back and forth through all 3 of my computers and 2 laptops.