Elop leaving Microsoft is no big surprise: Microsoft did not want to buy Nokia's bloated and (obviously) underperforming mobile phone division! Elop pushed it through regardless, giving Nokia's shareholders a decent chunk of money. (Anyone should have seen the axe of job cuts coming a mile away. Seriously, how is that a surprise?)
A business is a machine that makes money for its owners. How that money is made is a mere detail. Nokia have been active in logging, rubber products, and more. Mobile telephony is still a key sector; they just prefer making the infrastructure now, rather than the client devices.