It's not that buying Nokia solves MS probems in the mobile arena. It's that buying Nokia prevents bigger problems. A kinda defensive/offensive move, depending on which way you look at it. Bottom line - MS simply CANNOT at almost any cost allow anyone else to buy Nokia.

And who else would? Obvious candidate is Intel. They have deep pockets and with their Intel/Nokia/MeeGo strategy sabatoged by the Elopalypse no doubt Ballmer & Co. is not on their party invite list anymore. And that failure also means they are struggling as much as MS to stay relevent in the very mobile future. Both companies need a win badly for their team and Nokia is the biggest free agent available to boost the roster.