Why?
Because of digital streaming Interent music and because of Sirius and XM radio through satellite.
I have an old, old Fisher Studio Standard AM/FM tuner that still provides outstanding AM/FM and it is over 35 years old. I bought it because it was one of the first digital tuners. At the time, AM/FM were big, no CDs, no video switching VHS, Betamax or blu Ray DVDs. You either listened to 78 or 45 RPM records or reel-to-rell tape. Therefore tuner specs were critical and competiton produced some great AM/FM receivers and tuners. Yes, today, AM/FM is mostly an after thought!
The separation idea does make some sense only because a separate tuner is focussed on good specs and iIagree in many cases the AVR tuner is an after thought. The HD tuner in my 8002 is pretty good and even the AM comes in good with an external TERK AM -1000 Advantage Antenna.
The Cambridge 340 is an excellent tuner for $329, but does not yet incorporate the HD technology.
If you are really concenred about good FM then look for HD and a good dipole antenna. If you are really really a fanatic install an external FM antenna.
You can get some great HD FM tuners . The Sangrean HDT-1X tuner is an example that also has XM.
Music to my ears,
I don't have any experience of the tuner sections of receivers, but I have heard from many they have joined the race to the bottom.
I do not listen to AM. I have only owned three types of Tuner in my life. An old EMI tube one, when I was a kid, the Quad FM3 and the Quad FM 4. I use an FM 3 in our GF town home and in the first level system here and an FM 4 in the studio. I get excellent FM listening.
Now I did do an installation recently for a guy in the Twin Cities. I used a Sandjean FM/HD. We were pretty close to the MPR St. Paul transmitter. I thought the digital HD, which by the way does not stand for high definition, because it isn't, had a brittle quality to it, especially on a choral selection that played during evaluation. I preferred the FM.
The equipment was Thor TL speakers with brand new NAD electronics.
In England they have DAB. I have been able to do quick A/B comparisons between BBC Radio 3, which has the highest streaming bit rate, and FM. There is a strong preference for FM from all listeners.
The max bit rate supported by these systems is too low. If analog broadcasting goes the way of analog TV broadcasting, it will be a very raw deal.