Why Kaido keeps on fighting… and why doesn’t he dodge? Here’s my short theory on that.
I believe Kaido was betrayed by Rocks D. Xebec. Rocks ran away from the fight, and it left a huge hole in Kaido’s heart as he looked up to Rocks.
Now Kaido wants to prove to himself that he’s the strongest, and that he doesn’t need to run away from the fights or even run away from attacks, he wants to prove that he’s better than Rocks D. Xebec.
That’s why he’ll keep on fighting Luffy until he draws his last breath out of exhaustion. He won’t run away like Rocks D. Xebec did.