How exactly could a PM interview process (which is just asking you to walk through a bunch of design scenarios) give a stronger hiring signal than having developed a product the company wanted to acqui-hire? Honestly somewhat insulting that they made him go through a full external interview loop. At most it should have been some informal chats of the sort you get when transferring teams internally.
Wait, what? So if someone is a "name brand" celebrity, they should get to jump the queue and coast by with an "informal chat?" How is that fair? I don't care if I'm interviewing John Carmack, he's getting the same evaluation process I would give to any other senior candidate. Software Engineering's got enough problems with interviewing--it doesn't need an aristocracy that gets special treatment.
I am guessing that the average "higher up" at Microsoft does not know what AppGet is, or even what the priorities for package management in Windows are. It's just not a high level strategy thing, it's a low level engineering thing.