Winseer:
What other line of work does one see where those that are truly awful at it - still have a shot at being paid for it, but those that are truly best at it - are not even on the market to be paid for it to begin with? 
I know many examples frankly, including a university educator who turned to fencing (the kind with wood and concrete, not with swords).
More to the point, employers create their own reliability. Workers with steady employment tend to have steady lives, to be men of habit, to have wives who are women of habit, to have friends with similarly steady lives and steady attitudes to life, to have regular bills to meet and little savings, to live nearer to their workplace, to have reliable cars, to feel moral obligation to their employer, to fear the sack, to think and plan further into the future than just the day or the week, and so on. These are qualities and circumstances that tend to be forged over decades.
By contrast, most haulage employers (and indeed agencies) are recruiting from a very different pool. Certainly, most agencies are recruiting from a pool of habitual and hardened temporary workers.
Of course there are the incompetents or criminals who might be punching above their weight in terms of the occupation (or the condition of unemployment) they’d otherwise be in.
But most such temporary workers will have the individual qualities necessary to be reliable permanent workers. They just don’t have the permanent work. They’re not men of habit because their various employers are not employers of habit. Their lives are not organised around reliable service to a particular employer because they have no particular employer. They’re used to working when they want and not when they don’t. They’ve probably fired off a great many employers themselves, and are practised lion-tamers.
And if an agency worker decides not to get up on a Saturday morning for whatever reason, his latest two-bit employer is no loss to him. There are 25 more agencies willing to hire him the day after, and 25 more employers addicted to temporary workers who are willing to take him, because he’s still no worse a punt than the next man on agency, and if they wanted to be choosy they’d have to put the pay rate up.
Haulage employers who claim they can’t get the staff, are really just reaping what they have collectively sown over many years already. There isn’t a shortage of potentially reliable workers, just a shortage of industry conditions which actually condition them and keep them disciplined and motivated as reliable workers.
