Hawkins joined Kaido because he saw 0% chance of victory and escape but 40% chance of survival if join.
No doubt, he didn't join Luffy earlier because he saw only 19% chance of survival.
If he will see some higher chance of survival on joining Luffy, we are having Hawkins in alliance as well.
Also, Kidd is being portrayed with higher will power clearly now. Something on the lines of Luffy.
What caught my eye is that Hawkins said, 'Kidd kept on fighting until he collapsed'. So does this mean Kidd was not one shoted like luffy?