Nokia didn't ignore the iPhone. Its CEO described the threat exactly.

The usual story says Nokia ignored the iPhone. The record says Nokia saw it clearly.

In February 2011, Nokia's chief executive, Stephen Elop, wrote an internal memo that leaked. Our competitors, he wrote, aren't taking our market share with devices; they are taking our market share with an entire ecosystem.

The diagnosis was right. The trouble was inside. By 2009, Nokia was running 57 different and incompatible versions of its Symbian system.

So Nokia faced a fork. Repair its own platform and push its own alternatives. Or abandon Symbian and bet the company on Windows Phone. The logic: Nokia couldn't build a third ecosystem alone, so rent Microsoft's. Nokia chose Windows Phone.

Nokia's smartphone share went from 50.8% in the second quarter of 2007 to 3.1% by the second quarter of 2013. That September, Microsoft agreed to buy the phone business for an announced €5.44 billion, and later wrote off $7.6 billion of it.

So Nokia did not miss the threat. It saw it, then chose a response that handed its future to someone else. One case cannot prove that renting an ecosystem always fails. It does show that a correct diagnosis is only half a decision. Judge the response on its own.