The FSF has launched the "Upcycle Windows 7" petition, and if the opening paragraph doesn't persuade Microsoft to open source Windows 7, then I don't know what will.
"On January 14th, Windows 7 reached its official 'end-of-life,' bringing an end to its updates as well as its ten years of poisoning education, invading privacy, and threatening user security. The end of Windows 7's lifecycle gives Microsoft the perfect opportunity to undo past wrongs, and to upcycle it instead," the petition reads.
Yikes. At any rate, most users probably agree that Windows 7 already undid Microsoft's past wrongs, being absolved for the sins of Windows Vista. Hey, maybe the FSF should ask for Windows Vista instead. You know, shoot for the moon and land in the stars kind of thing. Something's better than nothing.
Moving on, the FSF has demanded that Microsoft release Windows 7 as free software for the community to "study and improve." The petition goes on to cite a precedent for this in the form of Microsoft's Calculator app being on GitHub, and claims Microsoft has "nothing to lose" by releasing an operating system that has reached end of life. Except, Microsoft kind of does have something to lose.
While Windows 7 is in EOL status, and that means no more free updates and patches for consumers, it isn't technically unsupported.
There's still hundreds of millions of Windows 7 machines, no shortage of which are business or enterprise customers that will be paying for extended support. Microsoft offers the privilege of paid extended support for Windows 7 through January 10, 2023.
For instance, the German government will be paying Microsoft $886,000 for one year's worth of extended support for 33,000 Windows 7 machines.
Joining Germany is Ireland, as Ireland's Health Service Executive has agreed to pay Microsoft roughly €1.1M ($1.2M) in extended support fees for 2020, and will be paying for extended support though at least 2021, for no less than 46,000 Windows 7 PCs. Those are just two recent examples.
Then there's the not insignificant fact that much of the codebase in Windows 7 lives on in Windows 10. In other words, the chance of seeing Windows 7 in a GitHub repo anytime soon is unlikely, to say the least.