Well, if you think Shavers beat Ali that you should tell you that Ali was quite beatable at the time. I've heard about the busted eardrum many times here without seeing a credible source any one of these times. But looking at the fight he sure doesn't seem very bothered by Young's punches. Whereas Norton and Shavers both unquestionably hurt him. Young didn't really do better than Norton, Shavers and Neon Leon. Actually he did less damage. So just what is the big deal about Young's performance?
Ali was in terrible shape in this fight. A portion of his poor performance falls at his feet. Jimmy should of been even more aggressive. However, if the fight was scored on clean effective punching and who landed more and made their opponent miss I think the answer is Young as the victor, Pretty clearly. Ali whether through mystique or as Don King's house fighter always got the benefit of the judges late in his career when his skills were eroding rapidly.
For me, Young wasn't even the technical boxer who did the best against Ali. Jones for example gave a young Ali a terrific fight with forward coming counter punching. Ali was still a bit green at the time, but in good physical shape and with the fantastic speed and stamina that he had lost when Young came along. Folley was well beaten in the end, but did very well considering how physically outmatched he was. Here he was the old man, facing Ali at his very best. But still he took the fight to the younger, bigger and much faster man and did as well as could possibly be expected. But just because Young ran a much, much worse version of Ali closer (and arguably won) his performance has reached mythical proportions for some. It's not really reasonable, though.