Regulation sets a floor for the race-to-the-bottom. Companies could set high standards, yet they usually meet the bare minimum. Improving standards costs money. Unless it's a requirement, it gets cut.
Regulation creates a barrier, sure - a good barrier is one which requires training, practices, and equipment to promote safety.
Likewise, with high regulation, there still people who drive recklessly.
Regulation creates a barrier, so its not easy for newcomer to enter and compete.
Becoming a good trucker still requires training, practices, and equipment to promote safety regardless of regulation.