No, they just don’t generally eat large or fast prey. Large sharks feed on smaller marine mammals, fish and molluscs, mostly. Plus they don’t have to worry about large prey escaping; if they bite something and it doesn’t die, they swim after it and bite it again. A crocodile has no chance of catching anything once it gets away from water, so it must kill with the first bite or at least hold on long enough to drown its prey.
One thing I don’t like about the mechanical bite test machines: When I bite really hard, I may suffer discomfort either due to crooked teeth, crooked/hard food, or uneven load on the teeth and jaw. This causes me to relax the pressure. The mechanical jaws will just crush until something breaks.
Do honest to goodness predators learn to ignore bite discomfort?
I can’t answer as to whether they have learned to ignore the discomfort or if they even feel any by our standards, but they do regrow lost teeth for their entire lives.
Each tooth already has a new, replacement tooth growing and ready to take over if the main tooth gets knocked out, which must happen frequently due to the forces you mention. In other words I don’t think they pull any punches when they are trying to catch dinner or defend themselves, even though it might cost them a couple of teeth.
OK honestly, how stupid and is this imbecile in the video to willingly and intentionally place his whole damn head into a croc’s open jaws without expecting something bad to happen? Natural selection in action, I’d say.