If there was ever proof that the expense of building hardware for proprietary systems is just nt worth it unless you are the one whose proprietary system will ride on top of the hardware - the Tablet PC is that proof. I shudder to think about the tens of millions, perhaps hundreds of millions of dollars that have been expended in the venture toward making a product line that would work with the soon to be defunct Tablet PC editions of Windows.
Imagine if those self-same manufacturers were to install GNU/Linux on those Tablet PCs. Imagine if they opened up their hardware to the Linux community to build a successful version of the Tablet PC and marketed it correctly. I can imagine that they could see a return on those hundreds of millions of dollars in investments in building a new line of products, the manufacturing capacity and the research and development.