What about Samsung and HTC? They have high-end successful Android phones. Though I haven't looked at the financials of the company or anything... are they not doing well?
Samsung takes 95% of Android profits. HTC, Motorla, LG, Sony etc get to fight for the rest. I wonder how long Google is willing to be Samsung's R&D department for free.
I don't think HTC is doing very well so it would be just Samsung and they are competing for the premium segment so the cheap Chinese phone are not really a concern for them, but Nokia needed something else to differentiate, hence their choice for WP.