Truck drivers do a lot more than just sit in the cab and drive.
Sure I guess there are operating models where you don't need one driver paired all the time with one truck but definitely can't just replace drivers IMHO
The fact that truck drivers do more than just drive isn't a necessity though. There is no reason why truck drivers also needs to be an unpaid loaders/unloaders and any other roles currently taking on by them. It's just a matter of "we've always done it like that". Businesses will reorganize themselves if it means a substantial reduction in transport costs.