The tuners used in HT preamps are not nearly as good as you would get in a dedicated tuner. Considering the generally horrible quality of FM broadcasting (at least where I live), I can see why there is not a lot of interest in devoting a lot of money to include a better tuner in a HT preamp.

I do have two separate tuners - one being a McIntosh tubed unit, vintage 1962, and a Phase Linear tuner from the 1970s. I have a 950 preamp which I use only for movie playback, but music listening goes straight through a tube preamp to an active crossover and EQ, then to the power amps.