You don't waste time on lesser talent. If a young QB on your roster has the best chance of succeeding, how exactly do you find that out? By tryouts and open competition. The best guy is the guy that shows the most potential and makes plays. That's the guy you spend your time on. The guy you hone and train. Anything else is a waste of effort. The Jets don't owe Clemens or Ratliff anything but the chance to tryout for the QB position. Nothing more, nothing less.
Eli Manning was awful in his first 8 games as well. As TJ improved leaps and bounds so will Kellen behind this line.