I would argue that they did not miss mobile phones so much as poorly execute on it. They knew mobile phones were an opportunity from the outset and made multiple attempts at gaining traction. But all the attempts missed. How many versions of Windows did they try out for the phone?

I have a Lumina phone running Windows 10 and it is a great phone. But it is way too late. Just because they know they need to be in AR/VR does mean they will be able to execute on it and win.