One of the reasons it's "a last bastion of manliness", if indeed that's the case, is because in many ways the conditions within the industry are far from ideal, and many women, especially those with children and other caring commitments, quite sensibly decide it's not for them, especially given the poor level of pay.
But it's starting to sound like you're sneering at truck drivers rather than showing any degree of empathy or understanding of the difficult job they do which, joking aside, many/most here are probably not cut out for.