Pain Tolerance is a huge factor too.
Thats my point, his haki wasnt strong.
Nothing to gift, its called narrative. They both know Barrier Haki, Zoro used it to stop Hakai no reason to believe Luffy cant. Oda just needed him out of the way so he had him sacrifice himself.
I see you ignored my other points though, is BB a haki master for being an endurance freak too?