This is the reason radio should not be factored into the hot 100 directly. Its consistently at odds with what the public is actually doing and if the public is here for a song the streaming and sales numbers will show it.
Radio is still important since people also call in and request songs to be played. Radio also impacts more listeners on a day-to-day basis so it will never go away (since it's a format that millions use in their car/at work etc). But it might need a smaller percentage in the Hot 100 formula.
But glad this song is rising on iTunes at least, it deserved to be a big radio hit too... dunno why Interscope didn't push it on radio with some deals lol