When it comes to electronics it is possible to measure to levels beyong human hearing infrequency and dynamic range, and with low level electronics it is fairly straightforward to achieve performance levels better than our ears can detect so measurements tell us enough to choose.
Anybody hearing a difference will be imagining it or subject to the placebo effect unless they are hearing way from competent kit.
With record players, microphones and speakers we can't engineer devices with even frequency response or always inaudible levels of distortion. Here it is a matter of whether you can hear it and what you prefer.
It is said people tend to prefer the same thing but in record players that is not my experience and it is possible but not easy to tune to taste.
Speakers in rooms are a different thing and strong opinions abound.
Dan D'Agostino is sufficiently marketing savvy to know Guttenberg's mantra is grist to the audiophile mill so what he says will be for marketing, so will the styling. The engineering, otoh will be sound - ie plenty of measurements, otherwise, apart from anything else, how could he quote a specification?
When I was introduced to him we chatted about engineering for a long time, I am sure he knows what he is doing technically.
Good measured performance means you are listening to what the recording engineer and artist released as a recording.
Poorly performing kit may be enjoyed but it is an effects generator not high fidelity to the recording.
A large number of expensive and popular pickup cartridges are considerably rolled off in the treble, for example. This may sound nice and mellow but isn't extracting the music accurately.
The other difficulty in believing that idea is that aural memory is short so getting a meaningful and reliable comparison by ear requires a very precise level matched and "blind" comparison, a bit inconvenient and not something non-technically minded folk tend to understand or even bother with.
Other "high-end" makers do all their engineering by measurement, but don't go on about it in their marketing, though some clearly don't.