Personally I'm pretty skeptical. In his provided measurements, even the lowly TL074 has noise down at redbook level and distortion well below what most people can hear.
It’s interesting that the TL074 is the other op amp used in the Luxman phono EQ. Night and day difference though.
But even then, I agree with you. For Moving Magnet use (34 dB of gain), the combo of the stock op amps were not too bad. It’s only in Moving Coil mode at 52 dB of gain that it is a real issue. Most DACs don’t need this type of gain. My real world problems were also with a very low output moving coil cartridge as well.
I think this is where a nugget of truth can lead down to a cascade of unnecessary op amp rolling.