I think it mostly depends on how nokia handles maemo. I see linux as the fast racer who started with a handicap: it began serious development later, but is coming up fast, thanks to a large mass of developers taking it wherever they see fit (and generating choice), instead of a large corporation deciding for its users
In the pc world, windows has been a monopoly ever since pc's become popular. Because it had the head start, everyone learned windows first and never looked further. In the mobile world, nobody has such a monopoly yet (and possibly never will), so now linux-based OSes have their chance. Seeing how fast Maemo grows (i only discovered it recently, but researched its history a little), it may be a real contender. Again, how well it does depends on how well nokia manages it, especially through publicity