dpop
FM reception these days can be very noisy. That's another reason why OTA audio processing is kept aggressive, to mask that noise. Another factor is FM stereo performance, which at best has a S/N ratio of -65 dB. If the same station has a decent high bandwidth stream, that S/N can be closer to -80 dB, or even -90 dB ...
Yes, digital has the s/n advantage, but it's of little value when the signal is lo-res lossy digital, which most radio streams are. (Yes, there are some exceptions, as you note. For example, Radio Paradise has great SQ, although it has no OTA signal.))
FM stereo reception and performance is not really as "high quality" as it is sometimes portrayed. It may be convenient, but it is rarely a high quality medium these days.
That's true - most FM audio is w-a-y over processed, and the HD signal can create noise in the analog signal. But there are notable exceptions.