They don't have to. Their track record for Apple has pretty much spoken for itself, and Google phones have managed pretty well too. Now with this news about Samsung open-sourcing everything for their phones is in direct contrast to Nokia's lack of effort to pull openness for its community. Nokia hasn't really had the best tangible track record despite all assurances of openness and support. Saying that 'marketing was right' over and over again isn't really going to convince me to change my opinions, whether they were right, wrong or not entirely and simply either right or wrong. When you parrot it this often, it begins to sound like you're trying to pit technical people against marketing people.

Sometimes, people aren't expecting a full upgrade. They're at LEAST expecting some backporting to fix bugs or openness to make up for the lack of the corporate overlords extending budgets for such closed-source efforts.