My 2d worth
Forget about Meego. It was another Linux spin-off, and there are plenty of those. There is no compelling reason why this one is different from any other. Moblin made some sort of sense when Intel thought it could squeeze windows out of netbooks and tablets to increase margins for it's chip customers. But Nokia has dropped the Maemo ball so many times that there is nothing worthwhile to pull out of the wreckage.
HTC and, to a lesser extent, HP and Samsung will offer WP7 phones for the rest of this year, then drop it like a hot potato: they already have somewhere else to go. This might be the inadvertent making of WebOs - or did HP read the writing on the wall when Mr Elop joined Nokia?
The big mystery is what will happen to low-end phones. Most of the world, from Nairobi to my wife's mother, don't want a smart phone: they want a cheap one. That makes phone calls. WPx will never be cheap, because M$ have a revenue mindset not a volume mindset.
This could be China's moment. OvTech, C-EASY, Huawei, and all the rest are waiting in the wings. They are more than ready. Hutchison Whampoa owns '3' and could easily want to join in. They have the world-wide contacts.
We are living, as they say, in interesting times.