If it was possible to export that data there would be apps to help people to process it further. No need to stumble around in XML piles. Your "makes no business sense" argument is not even Web 1.0 ;-) It's the ages old argument that was brought forward wrt Office file formats, pre TCP/IP network protocols and an endless list of other lock-in strategies. Even Microsoft has shed that retro attitude to some degree exactly because it does not make business sense in the long run. You need third parties to build on your stuff and that means you must set the data free.
But people only care when 3rd-party tools exist that they can't use. Right now, the ivory tower is okay, because the rest of the landscape is flat and barren.
I think people do care a lot about moving data between applications. There is nothing that comes up more often when end users need help. Today I was asked to move emails out of Mac Mail. Last month it was watch lists from a trading site to an Access database. Data silos are a huge problem and a productivity killer.
