Nexradio does just that. They only broadcast local radio stations in the immediate area. Not the whole us like tunein.
i can see IHeartRadio adopting that policy in the future where "Out of Market" stations are paywall and local area station as detected by IP Address/GPS will streamed for free for those in the market to help pick it up in fringe areas and areas where reception is poor indoors.
example, if you are in Dallas/Fort Worth, Texas area and you want to listen to 106.1 Kiss FM (KHKS), you can for free, but if you want to listen to New York City's Z100 (WHTZ, 100.3 FM) in Dallas/Fort Worth area, then you would need a paid subscription ofd IHR Plus or IHR All Access to access the station in that area.
internet streaming is pretty much hurting the music industry more then helping, i expect the free ride to end for music streaming services that act like a MP3 Player/6 dis CD changer radio/Jukebox and start pay walling them by 2020. and for those in the streaming radio station business, then it's time to end the free ride for out of market streaming and put it all stations not in your local area under a paywall as well. at the end of the day, radio and streaming on all platforms is a business and to make money, you need to change and adapt to the times.
streaming should be treated the same as cable TV was when it first was invented, charged and made to be only by payment to profit.