Ultimately, no. It may be interesting in understanding why a note is what it is, but it ultimately doesn't affect the fact that it now is that and has to be dealt with as such.
How far does this go? We should just play the notes, without having the first clue about what was going through the composer's head when he put them together? And that's supposed to be a more musically noble attitude than that outrageous one in which a pianist dares to see horizontally AND vertically- enabling ongoing appreciation of harmony from the manner in which it organically arises, as opposed to mere memorisation of a chord sequence?
But we move past that initial awareness - not absentmindedly forget it - and place that momentary harmony into a sequence of harmonies within which each voice has and takes it's part.
Still makes no sense, conceptually. So, you memorise a chord sequence and then stop processing vertical issues altogether? That's just a nonsense still, sorry. A good pianist carries on observing and FEELING the harmony, from how the voices produce it on a vertical level. They don't memorise a chord sequence like a jazz pianist and then refrain from paying any vertical attention altogether- out of some ridiculous dogma that falsely paints any degree of vertical awareness (within a grand scheme of awareness that obviously involves horizontal awareness) as a negative.
Post a YT of the Gilels you mean. I'm not familiar with his recordings of the Siloti transcriptions, and wouldn't want to guess at which transcription you mean anyway. I try not to comment on matters before hearing the evidence presented.
With that caveat, though, and as a generalisation, I'd also say that a note only overwhelms the vertical texture if all you are considering is the vertical moment. It doesn't necessarily overwhelm the horizontal texture, and that informs the vertical, even to the extent of creating an auditory illusion.
There's only one Bach Siloti that Gilels recorded:
Note the projection of the D at 2.29 and the Bs just before the end. You cannot do that without vertical awareness of hierarchy. The most intense melody notes are matched with LESS accompaniment and not more- or they simply don't register like that. Gilels varies the accompaniment and sometimes allows it to draw more attention. However, the awareness of length is always at its greatest when he keeps the competing notes within a small dynamic sphere. Although he is not significantly limited by the concept, his really remarkable moments of horizontal projection take it to the extreme. Elsewhere he merely keeps it in in check enough not to overpower. Pianists who do not continue to listen to the vertical heirarchy throughout the whole horizontal duration of the note cannot emulate that. Horziontal and vertical are one in this issue- not something that can be separated.
The recording you posted is accomplished enough but very lumpy by comparison and not terribly melodic. Nowhere near that ongoing horizontal intensity that Fischer and Gilels can coax out of a long note. I really don't like the way he brings out the thumb at the expense of the actual melody line- which is a classic example of a performer missing the extent to which overloading the vertical hierarchy kills the horizontal projection of a melodic line. To be perfectly honest, he doesn't appear to actually have noticed where the primary melodic line is marked (when it switches from left hand to right hand)- given that he does the same overloading of the melody on the first time and repeat. However, it's still a manifestation of how poor vertical use of tonal hierarchy kills the horizontal duration of long melodic notes. The places where his melodic notes do resonate through horizontally are those where he stops banging his competing left hand thumb and plays the semiquavers softly- in a vertically proportioned hierarchy.
I don't believe that a listener should EVER be required to do the performers work for him. Listeners should just listen. I know that the semiquaver line resolves on the D sharp at the end of that piece. However, that doesn't make me forgive that young pianist for failing to bring it out of the last chord- unlike Gilels, who projects it through the vertical texture, as a horizontally important completion of that line. Gilels does his job, but the young performer merely plays a singular chunk of undifferentiated sound, without reflecting horizontal context of lines in the execution of vertical voicing. I'm sure he knows that the D sharp is the completion of the line. But because he failed to delineate from the vertical texture, no listener will hear that horizontal completion (including myself, who obviously knows full well about it- but these shouldn't be merely for those who know the piece, but for any listener).A pianist who requires the listener to listen in a certain way to hear a musical result is not doing his job as a musician. Gilels and Fischer can MAKE you hear the horizontal length of a sustained note, by the vertical balancing. They don't grumble something to the audience about how it's supposedly their fault for listening vertically instead of horizontally. If a pianist wishes the listener to hear a voice horizontally, they must delineate it from any competing note at the time of of it's arrival, via a vertical heirarchy. And they must be capable of doing that on an ongoing basis. They have no business whatsoever complaining about how a listener listens if they only manage on that with 1 out of 4 notes of a subject. A note or two can sometimes be implied by horizontal context, but the performer has to man up enough to accept responsibility for bringing most of them out for real, off their own bat. Equally, they have no business expecting the listener to listen through long notes if they are unable to subdue the competition. How far do you propose to take this? If I hear a pianist punch out every note of a melody choppily, should I listen more "horizontally" and do their work by imagining a fluid legato based on better horizontal relationships? I'll listen to someone else who does their job, thanks. Singers don't decrescendo on every note and nobody would listen to one who does. To emulate that successfully, you have to first master vertical hierarchy throughout a note's full duration, in order to create the illusion that the note sings right through.
I'm not arguing that some pianists clearly have no idea of what they actually sound like. But there is no objective standard either - a note, and a sequence of notes, is heard subjectively. If your listener has a "fantasy" that distorts their hearing, you need to be aware of it so that what you wish to be heard is in fact what is heard. Indeed, manipulation of that fantasy is part of the art.
? You take a straw poll of an audience of 500 and then play to their individual subjectivities? I think not. I think it's just a little simpler to do everything you can to observe your actual sound- rather than keep getting lost in trying to imagine details that you ought to be listening to instead. Only the broad scheme can be done in the imagination. Sensitive playing adapts to the sound of the moment. Subjective issues aside, the closer you observe your sound by listening instead of imagining, the closer you will be to hearing the sound that the audience is hearing.