The Bible is a book used by a much wider audience than the Pope's followers. The pope at the time just tweaked the book to increase his followers. A very convenient reasoning from the Pope's perspective. So you seem to not be accepting that on why would a pope should and shouldn't do.
Since the time of the canonizing of the book, lots of history has happened where the pope of the time has softened some of what was traditional practices. Again, not sure why it is okay to accept some pope from historical time could canonize the bible, but a future pope would not have similar authority to make further amendments. He is the Vicar after all, and is infallible. Unless you do not believe that about modern popes??
I said you were trivializing it, not that it was impossible. My original comment is it's "far outside the bounds" of what has been traditionally done by Pope's. To suggest that the answer to the question on marriage is to introduce an entirely new canon to the Bible that appears to contradict previous books of the canon (I supposed he'd have to remove those at the same time) is simply unprecedented and has never once occurred in the history of the church since the Bible was canonized.
Since the time of the canonizing of the book, lots of history has happened where the pope of the time has softened some of what was traditional practices. Again, not sure why it is okay to accept some pope from historical time could canonize the bible, but a future pope would not have similar authority to make further amendments. He is the Vicar after all, and is infallible. Unless you do not believe that about modern popes??