Viridian...Some recent tests that I ran on my humble phono system (Shure v15mr) suggests that, to my surprise, some signal up to 35 KHz does actually exist on some records, (at a very low level) so I won't contest your suggestion that 45KHz is possible. The low end is, IMHO, the important difference relative to CD. For a CD there is no roll off the bass to limit groove modulation amplitude, or mix to mono to prevent stylus hopping, or feedback. And, my ears still work quite well down to 20 Hz, but are deaf (to sine waves anyway) over about 14KHz.
Regarding dynamic range, on my system the noise floor of a "silent" groove is about 80 dB down from the peak of a loudly recorded LP, and a similar test of a CD yields about 100dB. I admit that I didn't read your reference (web names that go on for two lines are a challange) but the ones that I have seen usually talk about listening to signal that is many dB BELOW the noise floor. Frankly I don't enjoy listening unless the quiet passages of music are well above the noise floor. A signal that lies well below a noise floor can be detected by computer processing and perhaps by ear, but I would not include that in a practical measurement of dynamic range.
Regarding dynamic range, on my system the noise floor of a "silent" groove is about 80 dB down from the peak of a loudly recorded LP, and a similar test of a CD yields about 100dB. I admit that I didn't read your reference (web names that go on for two lines are a challange) but the ones that I have seen usually talk about listening to signal that is many dB BELOW the noise floor. Frankly I don't enjoy listening unless the quiet passages of music are well above the noise floor. A signal that lies well below a noise floor can be detected by computer processing and perhaps by ear, but I would not include that in a practical measurement of dynamic range.