There's a couple of false assumptions here. Being FOSS doesn't mean being on its own. Nokia can continue to support maemo as a FOSS project. It may even be better because there are people within Nokia who want to kill maemo/meego/linux and getting some of it out of Nokia might be the best way to let it grow. There are ample precedents for companies using FOSS, and here the chance of someone using some derivative of maemo from FOSS is definitely higher than them using Nokia's maemo. Of course, there are other advantages I will not go into. I'm not saying FOSS is the best solution, just pointing out that it's not a binary black/white decision - there are shades of gray and should not be precluded as a possibility because of the few things mentioned.