This test should not be used to compare the sound quality of vinyl with digital or analog with digital. This test can only be used to compare the sound quality of the digital tape recorder model and the analog tape recorder model used in the test.
I believe we can't say that. This IS a comparison of what differences we hear between the playback of two different media.
I would think the sound is limited by the weakest link in the chain.
In the digital chain the DAC plus output filter would probably be the weakest link. In the analog chain the weakest would be the vinyl disc itself and it's RIAA playback ( tone arm/cartridge/preamp...apart from other factors).
We can't compare apples to oranges . However we could have preferences on the reproduced sound depending on what our ear tells us , which is different for different people......not to mention various biases we develop for sound over the years.
Technically the vinyl medium introduces a lot of distortion in playback especially due to the tone arm geometry errors and the cartridge itself.
Digital has typically far lower distortion. Additionally the digital system can produce a very flat frequency response whereas the the vinyl playback is never as good as the response of the playback preamp which might be accurate to as low as 0.01dB ( RIAA playback error !). At both ends of the spectrum. HF being particularly bad. Just look at the playback curves even from manufacturers.
But they do point out that if the source signal is identical for both "recording systems" the eventual playback on very good equipment favours the Digital system, for quality. Very easy to hear if you listen to very well recorded drums and instruments and also difficult sounds like wind instruments and even the piano. Digital does beat the analog for accuracy. 30 IPS open reel does sound very good but is also band limited and has higher levels of inherent hiss than an equivalent digital system. The recorded signal on a vinyl disc is far inferior to this.
Medium quality digital ( today most systems are pretty good !) is far better than medium quality analog . A good tone arm and turntable is quite expensive. A medium priced cartridge ( $100/- ?) is not half as good as a very expensive one ( $500/- and more?). Typically good for only about 500 hours of playback because the stylus wears off. With pristine playback conditions it might manage to reach nearer the specified 1000 hours lifetime for the stylus.
In another test they showed how much harmonics were being produced in the analog setup. This colours the sound and depending on where the harmonics are it could appear to sound "rich" ! If we like it, it is because our ear possibly likes that sound over the original distortion free sound.
It's like a musical instrument. The harmonics generated is responsible for instruments to sound different. So all violins don't sound the same. People prefer some violins over the others. But none are really 'bad' !
Here one might prefer the vinyl playback as it has harmonics that maybe one likes ! It's not because it's technically a better playback medium. It's worse for sure. But if we like it, that's where the money will go.
As clearly pointed out, the psychology behind the acquisition ( handling the disc and colourful printed large cover !) and playback of the vinyl disc makes us part of the playback scheme. In digital, the medium is very small and we don't really feel part of it. This will be worse if we used memory devices to play back audio.
It's like a party. If we sit alone with a drink and can't really mingle with the crowd , it will be unexciting. But if we can be part of the party and mingle with everyone , it becomes more enjoyable. Not quite the same thing but something like that !....feeling like we are also involved.....
We pick what we 'like to hear' and not because it's really 'better' technically than the others ! So it doesn't matter if the vinyl medium is technically inferior to a good digital system , if we like what it does , then that's what we would pick ! Remember that the mastering engineer has total control over how the music will sound .
To test your own preferences , play your music through a system with just a bit of bass and treble boost of say about 3 db( and maybe mid range lift or cut). Listen to it this way for a couple of days. Then shut off the eq or tone control and listen to it 'flat' again. The music WILL sound flat , lifeless, for a while !