Increasingly, Microsoft and Apple are seeing developers as the enemy. Sure, on the one hand they need the outward appearance of a rich software ecosystem, but on the other they feel the need to control it ever more tightly. OS X won't even run non-Apple-approved software in the future and Windows will quickly follow suit.
This is all because both companies have realized something we developers haven't grasped yet: they will be making their money as gate keepers, not as innovators. In fact, innovation is frowned upon - nothing illustrates this better than the OS X Sandbox mechanism and the politics of the App Store. Microsoft, already grappling with the looming specter of irrelevance, will have to copy this. It seems that for OS vendors in this decade it's either "become an autocratic despot or die".
If this keeps up, computers will become seriously limited devices in the near future.