Thank you! The Teamsters union (and locals), which actually represent truckers, supported AB5.
Not to overstate the obvious, but that's pretty much the entire point of unions: by working collectively, individuals aren't directly competing against each other, forcing management to pay higher wages, with the goal being that the wages paid are higher than any individual could make if the union didn't exist.
Joining unions is impossible for many. I once lost a job because the union insisted that I be let go rather than let me join. It was not a performance issue.
Independent truckers don't have management. They make more money and don't pay union dues. That's the whole point, and why the Teamsters want them gone.