First off, "famous" as a criteria for assessing virtuosity is problematic at best.
Additionally, the ability of a particular audience to discern quality is also problematic.
What it comes down to is that music is not just a sequence of notes arranged in a particular juxtaposition to each other. Music is communication, it's a form of core emotional communication.
Take a piece of music and play it at 130bpm, then play it at 127bpm, and it might turn into a very different piece, far more expressive more moving, more connecting.
The art of phrasing a melodic line is extremely subtle, but easily discernible. A midi file might play all the notes "exactly as written" and it sounds very good, but then a true player plays the same phrase and it sounds "like music." The difference is milliseconds of timing, micro-decibels of difference in emphasis, maybe 0.001 percent difference, but the difference in what we perceive is stark, obvious.
The experienced player doesn't "fight" the music. Imagine an analogy, of two skiers going down an intermediate slope. they ski together, and to outward appearances the novice is skiing just as ably as the expert, but when they get to the bottom of the hill, the expert is calm, unruffled, and the novice is breathing hard, exhausted. They both ran the same hill, followed the same line, on the same snow surface, with the same skis. The expert let the mountain and the skis do the work, the novice fought it and muscled it the whole way down. (I'm the novice skiier, btw)
This is the same idea between the two pianists. The novice is functioning on the "remain on skis for duration of run" level, the virtuoso is functioning on an entirely different level of subtlety.