I'm from India and I've been looking to buy a smartphone in this price range for sometime. The Lumia 520 seemed really attractive as it was the only phone in the $200 price range that wasn't crap.
The Moto G looks really compelling and if its available for this price in India I would buy it in a heartbeat. If this phone is as good as claimed (and thats a big if) then Samsung and Nokia stand to lose a lot of ground.
And as for the $50 price point I'm not sure you can provide a true smartphone experience at that price.
There is a lack of usable smartphones in this price range and the longer it goes unaddressed the more ground Android will lose to phones like the Lumia 520.