I am fortunate to have a decent piano to practise on, just a terrible one for lessons.
I'm sure Neuhaus and Berman knew what they were talking about, but the problem is whether a student can ever learn to make a poor piano sound good (and then ultimately make a beautiful piano sound beautiful) if her teacher never has the opportunity to show her how to make beautiful sound on a proper piano in the first place.
I can imagine Neuhaus's statement making sense for conservatoire students who first receive their training on proper decent pianos. Presumably, having this foundation would then equip them to work with substandard instruments, without this affecting their playing.
Which is not my case: although I work with a good teacher on advanced repertoire, I have never been trained in a conservatoire or a specialist music school. In lessons, whenever I am not playing something right, the most frequent comment I get from my teacher is that I should make the piano sing.
This is quite frustrating for me. Often my teacher would demonstrate what it should sound like, but some times I simply cannot hear the difference. Often my teacher would say I am playing a particular phrase better on a second/third attempt after he has made some comments; again quite often I would fail to notice the difference. I often wonder whether this would be the case if we did not have to put up with that poorly maintained Chinese made piano with a European sounding name.
Perhaps I am just making excuses for my lack of progress. Perhaps I should just imagine I'm playing a lovely Steinway all the time. After all, pianists live with many illusions in their playing most of the time, e.g. tha they are creating the sounds of different orchestral instruments.