There is a benefit to having FM radio on a phone. My Lumia 900 is completely capable of playing a clear broadcast of the local stations here without much (if any) interference. I know when I pick up the L920 from FedEx this afternoon I won't have my own music loaded into the device. This is where streaming music comes in though, right? I have a rather generous data allowance on my Family Share plan, and I know in the months I've been with AT&T that I have not gone over the 15GB I have for two lines. But, why should I have to fork over a portion of my data allocation for FM radio?
TuneIn is an exceellent application. I used it on my numerous Android devices and I bought the pro version to support the developer. Unfortunately, it isn't an actual FM radio. I've had smartphones in the past with the FM radio built in, including two devices made by HTC. I wasn't in a favorable location at the time to get clear reception so I never took advantage of it. That being said, I find the capabilities on the Lumia 900 to be far superior to that of the HTC Incredible I attempted to use the built in raido app on. TuneIn isn't a real radio. It's an application that taps into the streams of FM stations online and there is a delay on top of the broadcast delay. If you are just going from an a to z vantage point, yes it ultimately does the trick and gets you the FM feed. It isn't 'live', subject to data coverage versus actual FM reception and cuts into your data allowance.
No smartphone is perfect. There are compromises people will choose to make with the Lumia 920 coming from the Android and iOS family of devices. Shoot, there are compromises coming from Windows Phone 7.x devices. The point is one little thing - this is little - shouldn't prevent you from getting the device. If you want to make the argument FM radio could be life saving, like when the networks were down in the northeast due to Sandy, its pretty valid. Then again, I don't know how much I'd be relying on my smartphone during that time other than making phone calls - using the radio or internet would be disabled by choice so I could focus on calls and text messages. I personally own a weather radio for that reason.
HTC's soon to be former flagship Android device the HTC One X has an active FM radio, but AT&T had this disabled. If you manage to root the phone and install a stock ROM with the missing apps included you could listen to radio through headphones. I wouldn't say that FM radio is dying, it's just that it isn't something the carriers can monetize and use as a legitimate selling point of the device. Now if they began building phones with SiriusXM pre-installed with a receiver then subsidies could be netted from that and SiriusXM could be billed on your wireless account.
Carriers are reaching a fiscal cliff of their own - as modern smartphones continue to improve there are less services that have to be paid for or that can be sourced from outside content providers. There is less to monetize on by the carriers directly compared to several years ago. The last refuge for them is billing for the data consumption and controlling how much data you consume. Yes, go ahead and stream Spiderman - that will cost you x out of your data package. Once you hit 2GB, 3GB or 5GB you'll be dinged for additional data. And more after that.