What I find interesting about all these cases is who knew that this was happening? Were Steve Ballmer/Larry Page/Mark Zuckerberg/etc. as surprised as we were when this all got released? I wouldn't be surprised if they were (with maybe the exception of Mark since it's a smaller company).
Sure, but I don't think many people at Microsoft have security clearance to begin with. Like when the NSA reached out to some middle management Joe on the Outlook.com team, he/she probably did not have security clearance.
Entire groups of people at MS have clearances. Their software runs large chunks of the DOD, they can and do put consultants on site in secured locations when needed. Who else is going to fix an exchange cluster that has been mis-configured by a lowest bidder tech?