This sums it up pretty well, I guess.
Given two tones with identical final hammer velocities and, as a consequence, identical intensities, listening musicians were able to discriminate between struck tone (finger starts from above the surface of the key) and pressed tone (finger starts in contact with the key) by cuing on the adventitious sounds produced by the finger striking the surface of the key. Not perfectly, but better than chance. This is with dampers. It would not be surprising if, without dampers, additional adventitious sounds would make such discrimination more reliable. None of this tells you that great pianists with a beautiful tone have a beautiful tone because they artfully manipulate these small effects, as opposed to, say, artfully manipulating the speed with which they end a tone by releasing the key, or the way they match the volume of adjacent tones, or the way they overlap or do not overlap sequential notes, or the way they voice chords, or the range of final hammer velocities they are able to attain with either a struck or pressed tone etc.
I never denied the aspect of hammer speed, but that in itself is not enough to explain different qualities in tone in the same dynamic range.
What makes you think that whatever sonic differences occur, they are NOT due to differences of hammer speed?
Do you not think that the surprisingly large amount of noise the piano yields when you strike it vs when you touch it properly (as demonstrated by striking the lid or any other wooden part of the piano) will have any effect on the vibration of the strings? The hammer striking the string sets one set of vibrations in motion not only in the string being hit by the hammer, but in all the other strings and the wooden parts of the instrument as well, most notably the sound board. The vibrations of all these parts are what we are percieve as sound when they are transmitted to our ear via the air. If you then send a different set of vibrations through these same parts as they are amplifying the vibrations of the strings, a set of vibrations that are the result of striking the instrument, vibrations that sound like a hollow noise, it would be conceivable that the sum of these mixed sets of vibrations would sound different to our ear, no?
Yes, sure. It's conceivable. But I also find it conceivable that the vibrations created by the key-strike are irrelevant or virtually irrelevant, and the difference is entirely due to hammer speed. Without proper scientific tests, we'll never know.