Driving trucks is more difficult. For instance trucks are mostly (all?) unsynchronized manual transmissions. They take skill and experience to operate.
It's also more difficult safely braking/turning/accelerating a very heavy load like a loaded trailer as opposed to a passenger vehicle.
Some local trucking businesses in my area are training people to drive since there's a shortage of drivers. It takes a while to get someone to the point where they can get their commercial driver's license.
