Typically that's around when the bed gets big enough to haul a sheet of plywood or drywall safely.

I said nothing about safety.

The tests have determined that was a lie

Nice to see you've realized it's a compromise and not some slam-dunk about the character of whoever's driving it based on no additional information.

That being said, truck bros can be as insufferable as anyone else with an ego, they're just easy to pick on