I think the real key, though, is that Nokia didn't particularly want mass market success with the models released so far. It was an R&D platform that was mostly used to help development and generate a community (which it'd be really sad to see them toss away with with the Maemo 5), and it's only now starting to move into the big leagues.

Now, whether that was a wise decision is certainly up for debate, but it seems like Nokia's market position so far has been exactly where they wanted it to be.