This is true as far as it goes. Nokia and Samsung between them hold most of the under-$100 price band in mobile phones, so it's not just Asha but ultra-low-cost phones where Nokia is holding ground.
But this is no longer most of the phone business. Nokia used to be in a class by itself, with 35% of the whole handset business worldwide. That is down to something like 5%, and that part is the low-margin business, so margin contribution makes that picture even worse.
The bad news is that $50 Androids are coming and $90 Androids are pretty good. That's right in the Asha price range.