Several drivers for the N900 are closed source. I'm not saying this is Nokia's fault in that Nokia may/may not want to open the drivers, it very well could be the manufacturers fault, however it's Nokia's fault for using hardware that requires them to keep it closed.
For all its faults, and I will grant every one of them, Nokia still comes closest to providing a true, viable handheld computing experience. That in fact is likely one of the problems for the company: others have tried and failed. Nokia has screwed up on many fronts, but at least they're still trying to find a way to make a mobile computer work. That's why many in the community grit their teeth over missteps and keep trying.
They're maemo and MeeGo... "Meamo!" sounds like what Zorro would say to catherine zeta jones... after she slaps him for looking at her dirtily...