It is important to make a distinction between what they make and what they take home. In the US, workers subject to the DOT's "Hours of Service" rules (truckers, train crews, airplane pilots, etc) get very generous tak breaks and take home a far greater percentage of their earnings than most workers.

I made nearly 40K my first year in trucking and had no problem clearing 50K each year after that, and my total income tax rate was exactly 9%. I moved to a state with no state income tax and life was pretty good for a while, until I got tired of trucking. For those who enjoy it, it's not a bad income with very low barriers to entry.