First, is that you are of course looking at this from the current perspective. Let's time warp ourselves back to the introduction of Maemo. Maemo was pushed by Nokia as the open source alternative to other mobile platforms and encouraged it in that way (and others did as well). At various points along the way, people realized that Maemo wasn't going to live up to the open source promise. In that sense, we are not in the position, IMHO, of asking Nokia to open something meant to be closed. The community should be allowed to maintain software that was posited as being open and able to be maintained by the community.
Second, Symbian. Closed for many years and never described as open, and yet they did the heavy lifting necessary to open source it when there was no preexisting expectation that they would. It can be done.
The arguments being advanced for opening Maemo components is not ROI or morals. There is a history here and decision shouldn't be made based on a shapshot of today's circumstances. If so, then see my comments below.
Much the same thing could have been said two years ago - "Maemo 4 is certainly more open than other platforms, and Fremantle is definitely shaping up to be more open yet. Given the relative incompatibility of the new OMAP chips, I'd rather have a modern computer with Fremantle 2 years from now, than have a fully-open (even including applications) Maemo 4 at the same time, and be stuck running it on my N8x0."
See how I did that? It seems like we are in danger of accepting a recurring pattern of using technology upgrades as the reason for abandoning the open source approach.
If so, when does the pattern end? What comes after MeeGo? This is the forced software upgrade roller coaster to which open source Maemo was supposed to be the alternative.