I think it is fair to say that the concert repetoire of the early romantics was a lot more geared to their own works than that of other composers, but then they were living in the golden age of the pianist composer (albeit they did not know this at the time).
When Thalberg was touring the States, it was still uncommon for pianists to give solo recitals and often there were other musicians and singers involved. Although Thalberg probably did play Bach in private, i doubt if he did in public, because concert goers came to see him play his own works.
There is record of Thalberg playing 2 Beethoven Concerto's (3rd and 5th) in concert, but then he only played the 1st movements. Whilst he did get great reviews from the critics, the public were not impressed as this was probably to much for the 1850's American. So in affect, by playing his own works and other operatic transcriptions, he was only giving the public what they wanted.
As the 19th century moved on things began to change and if we look at the concert repetoire of pianists like Von Bulow and Rubinstein, we see Bach, Haydn & Beethoven much more frequently. Along with Clara Schumann they showed that solo concerts with a more varied and serious vein were both socially and financially acceptable.
When people went to see Liszt & Thalberg, they wanted to be amazed and they were. When they went to see Rubinstein, Bulow and Busoni, they were educated.
Thal