Agreed, but a nice coating of napalm would make VERY quick work of the guys in the open areas of M-3's, M-8's, M-16's, and Osti's.
Buttoned up tanks might actually survive if they weren't in the middle of the burn pattern and thoroughly covered, but rather were on the edge and got splashed.
Even a half decent SPLASH of napalm on an open vehicle will cover the occupants, regardless of whether it uses up the oxygen. Get SOME on a buttoned up enclosed vehicle and if it didn't cause something to cook off, it might not knock it out.