I think your dreaming by saying Dempsey keeps a cool head, glides side to side and chops George down. Dempsey never went anything but full steam ahead in his entire career, especially when hit. You are confusing the fact that against very fast boxers such as Carpentier ( for a few rounds) and Gibbons he did not do so effectively. He did not do it effectively because he could not. It took him a few rounds to nail Carpentier and 15 to decision Gibbons.
The Sharkey fight is a terrible example. For the first five rounds Sharkey kicked the shit out of a semi-shot Dempsey. Dempsey showed tremendous heart and a good chin to survive. Then, as Sharkey started to tire as he often did, Dempsey, still boring in, caught him. However, this was no way Dempsey playing it cagey. He simply kept moving in and caught the other man.
Foreman would have tore Dempsey's head off. He would have speared him with that monster jab. He would have crushed him with terrific uppercuts and hooks to the body. They really do not belong in the same ring. It is a terrible clash of styles for Dempsey. George was way too big, strong and hard hitting. Why not have Tony Zale fight Rocky Marciano ?
I have always felt that Dempsey gets an incomplete as a champion in my ratings. He had terrific heart, tremendous power, speed, heart and a great chin. However, once he won the title, he became an inactive fighter and regressed from the progress he made with Kearns in 1918 - 1919. He never became the best he could be. Dempsey would have had to have been the best fighter he ever might have been to have a chance to display the discipline to fight Foreman like E says he would. I don't believe he could have based on his actual career. It's completely romanticising the guy.