Earlier quoted context omitted.
Nokia was well on its way down before Elop. It's not fair to pin that on him. But, it did seem pretty clear (even then) that his turnaround strategy involved a Microsoft purchase.
I don't think you can call something a "turnaround strategy" when the result is to cause the company's value to nosedive so far that the most viable means to salvage any of their investors' money is to divest them of their stock at a significant loss. From the Nokia stockholder's perspective, even if by some miracle the company were to subsequently prosper under Microsoft, by that point they no longer own it, so how…
So, the benefit for the shareholders is that they won't loose any more money than they already have. Microsoft has provided a decent backstop to stop the loss in value.
Plus, I haven't seen what Microsoft is actually buying... they may end up leaving the backend infrastructure products as a separate company, which would probably leave shareholders with some value.