[jedieaston]

I think it's more likely than it ever was (whatever that means), given that their revenue is not all that reliant on Windows anymore. Their apps run in the cloud, on mobile devices (not Windows Mobile), and on Linux (MSSQL for Linux was unthinkable a decade ago). If they could open source it, give away home (and pro?) for free, then they could outsource even more QA to the community and still make the real money off of Enterprise and Azure hosting.

The problem is all of the binary blobs they used in developing Windows (the zip library is a simple example) are licensed from third-parties that probably don't want their software open-sourced. The libraries would have to be reimplemented for the OS to be usable (not saying it wouldn't/shouldn't happen, it'd just be a hurdle).