Is not a threat to anyone. Not even BlackBerry.
Your company lost the mobile wars. Suck it up. Nadella knows it's a hard sell breaking into a market. To break in you've got to break the chicken-egg cycle of getting apps on your platform. Metro wasn't the killer UI that it needed to be to pull users over in the absence of apps. Microsoft, if they really are committed, have to play the long game, basically replicating features until they can switch out the OS (the thing that runs apps, and not so much the UI) and not have users notice. However all the apps are digital data silos, vehemently protected by their owners. Don't expect it to be easy, or cheap. MS dropped $10B to get Nokia and look how that turned out.
Ultimately, MS stagnated, developers defected, and now no real innovation happens on Windows, and it's a hard sell to get mindshare back. We've seen a future that doesn't involve MS. Nadella knows this and is recapitulating for sins of his predecessors. It will take a long time because there's no real reason to continue with MS. Everything is platform independent now. Except phones. It's a losing gambit all-around.