If you want to go to politics, the sad reality is that Elop was neither a Trojan horse nor even the thing/person that killed Nokia. What is true is that Nokia was managed as an amalgamation of internally competing departments. The board and the C-level managers (already way before Elop) saw this as a good thing, or at least were too meek to stand up to the department heads. So when the Symbian team did everything it could to harm Maemo/MeeGo (maybe because they saw it as a direct threat to their job security), nobody understood this was massively hurting Nokia as a whole and not serving their customers.

What's more, even if somebody did understand this, any concerns would have fallen on deaf ears as Nokia also had a culture of corporate arrogance. It saw itself as too big & successful to fail. They could make whatever mistakes, but it was alright because they could always revisit and make better decisions later. I don't think they fully realized how wrong they were even years after the Android/iOS duopoly had already solidified - considering how immense amounts of money they kept spending (under M$) in trying to bootstrap the Windows Phone ecosystem that was always destined to fail.