[oblio]

I'm not from Microsoft, but I think they're probably working on stuff like that, it's just a monumental task at the start, since they've probably licensed many components from companies that probably aren't around anymore... so you'd have to chase current license holders, which can be super tricky.

Besides the fact that they have to scan the code, remove offensive bits, figure out if some code is still in use and it might have security vulnerabilities or could disclose things they don't want disclosed, etc.

I guess they're slowly open sourcing kind of stand alone components, to bank on nostalgia.

I wouldn't be surprised if 20 years from now all the Windows plumbing is open source (it's not a money maker for them, anyway), à la Darwin and MacOS, and they just keep the management layer proprietary: settings, shell, UI toolkit, etc.