The issue with Windows 7 pricing

The page in question is here : http://store.microsoft.com/microsoft/Windows-Windows-7/category/102

The pricing in question is this:

$49 for Windows 7 Home Premium

$99 for Windows 7 Professional

Okay, these are the upgrade prices... which are cut in about half. Microsoft also states that the pre-order on upgrades is good as long as supplies last and classifies these prices as a limited time offer.

Question: How actually determines how much supplies are on hand, and what their value is?

The answer is of course Microsoft. It's quite literally impossible for Microsoft to run out of supplies, since they are the ones making the supplies available.

It's a cute trick though. By making the prices for Windows 7 very competitive now... as the Windows 7 Home Premium upgrade is less than the cost of most Xbox 360 and PS3 games, many consumers will feel they are forced to buy now rather than paying out the regular prices later.

Thanks Microsoft, I do intend to avail myself on one of the Professional upgrades... I do need to know how to fix such installations of course... but stuff like this isn't likely to make me move away from Mepis Linux.