Selling something for $150 off-contract isn't anything to get excited about when the developing world (India and China mainly) already has huge market penetration from the likes of Samsung, ZTE, SE etc. - they are all selling equally capable phones at similar price point.
I.E. the situation is not very different from western markets - Samsung/Sony/ZTE already have a mindshare there at low and high end - even if you forget the low end iPhones. Plus to Nokia's detriment, Samsung can always release their "better" $150 Windows Phone in those markets.
Also the app situation isn't changing - at this point they really needed the app development scene nailed - Microsoft hasn't even released the SDK for WP8. Developing world is not somehow going to ignore that and spend $150 buying a dumb phone replacement.