If Jess Willard had defeated Luis Firpo ...

Yes, I think you're right. That must have been Rickard's gamble, and it worked!

In watching the footage of the Willard-Floyd Johnson fight, though, I think big Jess was in better shape in 1923 than he was against Dempsey. It's not like he had such a vigorous career by the standards of the day, 28 fights in 12 years. Granted he was four years older, but he wasn't as rusty since he had just passed his big test with Floyd Johnson two months earlier. So he had probably been training pretty steadily for four months or so. So he actually might have been able to put up a better fight when he fought Firpo than he had in 1919. Still, I can't see him lasting much, if any, longer against Dempsey than the three rounds he lasted in the first fight. I've always been intrigued by Willard's comeback.