It is merely MS placing artificial restrictions in hope to force W8 adoption.
As if developers are a huge percentage of all PC users
Application development can be divided in two groups:
Those that develop for a platform because there is a large potential customer crowd
Those that develop applications on a platform because it provides the best support for creating it in an efficient, reliable and cost effective way and customers that willing to buy these applications including the OS stack.
In my opinion the second one is a bit more risky, but if you have a great app that's the best in the crowd, people are even willing to change OS in order for it to run.