> Because the two clefs are symmetrical around middle C. Line "6" of the bass clef is line "0" of the treble clef. They are not two different clefs, the are two halves of the same 11-line staff.
Well yes, but I don't see why it's better to be symmetrical around middle C vs symmetrical around the B below middle C. Make them two halves of the same 12-line staff instead where the middle two are invisible rather than the middle one.
Even if there truly is an advantage, I doubt that it would overcome the disadvantage of arbitrarily making someone learn a different mapping between what they see and notes for the different hands. On top of that, for piano, I think it's an additional advantage to have a lower low clef - keeps common chord bass notes closer to the staff, and cuts back a bit on the ledger lines.
Well yes, but I don't see why it's better to be symmetrical around middle C vs symmetrical around the B below middle C. Make them two halves of the same 12-line staff instead where the middle two are invisible rather than the middle one.
Even if there truly is an advantage, I doubt that it would overcome the disadvantage of arbitrarily making someone learn a different mapping between what they see and notes for the different hands. On top of that, for piano, I think it's an additional advantage to have a lower low clef - keeps common chord bass notes closer to the staff, and cuts back a bit on the ledger lines.