If people would suck cock to pay for their drug addiction, then they would be just as willing to scrub toilets for minimum wage to pay for their drug addiction. They can't though, because of piss tests.
But they're not willing. And they'll often just cause more damage/loss than they provide in benefit to the company. Even the most benign drug which people claim is fine is one that makes you lazy and slow. Why would you employ someone so addicted to it that they can't abstain for a few weeks?
"Piss tests" filter out a lot of anti-social behavior.
You do not understand the mind of the people in that position. They, generally, are not nearly so rational.
A janitor needs to be reliable, it would be tough to manage someone who only wants to show up and clean toilets when they’re desperate for a fix. Maybe someone can build an app to coordinate that /s
I highly doubt that anyone is doing 8 hours of BJs a day to pay for their habit.