[jyl]

Rick, if the borrower fully repays a mortgage, the bank has taken zero loss. Disagree?

If there is a loss, but the bank has taken zero loss, then that loss is all taken by the borrower. Only two parties to this deal, after all. Disagree?

Assuming you agree to this point, the remaining question is, was there a loss? I suppose that depends on future house values and the rent vs buy economics in the meantime.