Beethoven was limited by the piano technology available during his lifetime. It is interesting to speculate that perhaps with advances in technology perhaps a future composer will expand the possibilities of piano music yet to come
I recently bought Hyperion’s CD (no SACD available) of Marc-Andre Hamelin playing the opus 106 Hammerklavier Sonata. According to the notes, during its composition Beethoven was given a Broadwood piano from London. Like Viennese pianos of the time, these had a six octave range, but started half an octave lower at CC compared to FF. The first two movements of the sonata use the higher range, the last two the lower one.
So it would seem that Beethoven did indeed compose for a future instrument, since no single piano he was aware of could manage all the notes in the Hammerklavier Sonata.
Similar thinking is behind the Stuart and Sons extended keyboard instruments, which have some other revolutionary features including a fourth pedal, which moves the hammer closer to the strings for really soft playing. The strings couple to the soundboard vertically rather than horizontally, and transmit more sound energy than conventional pianos. They are deliberately designed for a livelier sound than say Steinways or Bosendorfers.