As we talk about the differences between the Grotrian and Gaveau, it makes me think of the broader marked and fascinating differences among piano brands and their timbres. I'm not sure which was the chicken and which was the egg--the piano or the "school of playing", but I think the latter--that is that piano sound reflects a particular culture of pianism. In other words, pianos were probably designed and voiced to reflect the pedagogical/performance demands of the times.
In France there were Pleyel, Erade and Gaveau pianos. In the Paris Conservatoire there was the "French School" of teaching with emphasis on a hand position of curved fingers, pearly passage work in Mozart, and a tendency toward a drier almost nonlegato sound in playing that came down from Pierre Zimmerman, Antoine Marmontel, Louis Diemer, and Marguerite Long. And it seems too that the pianos of the day supported that approach in playing the music of Saint-Saens, Faure, Debussy as well as the more classical, cooler works of Ravel. As to pianos, it seemed as though the harpsichord and clavier sound had not been entirely lost in the French pianos to some extent. Thus, it was difficult to play legato on the Erade (although Paderewsky tried for years believing he could make that piano sing). Pleyel seemed somewhat bright and lacking a profound depth found in some other pianos. Gaveau was the most versatile of the three. In fact if Artur Rubinstein could not get a Steinway for an engagement, he would select Gaveau.
Now move over to Germany with its "sturm and drang" and composers like Beethoven, Brahms, and Schumann with all their heavy drama. That called for a bigger, more solid piano sound like Grotrian-Steinway, Hamburg Steinway, Bechstein, etc. used to good advantage by Hans von Bulow, Carl Reineke, Emil von Sauer, etc. Here again, I don't surmise that artists simply adapted to pianos such as they were, but rather that the pianos were designed to best produce the music of that culture.
I guess if I had a big house and plenty of money, I'd want a Baldwin SF10 (7') and a NY Steinway B (6'11") in my music room. Any Germanic music would be played on the Steinway. All impressionistic music would be reserved to the realm of the Baldwin. The pianos could then fight over Mendelssohn, Chopin, Rachmaninoff, and Scriabin.