I'm familiar with that for say, digging a ditch, or the n-martini lunch. Less so with "perpetually drunk and homeless" factory workers operating potentially dangerous machinery.
I interned at Daimler-Benz and assembly line workers had company-employed drink trolleys which would take your order early in the shift for what partially subsidized drinks/snacks you wanted delivered for your breaks during your shift. A tone would sound in the factory and workers would converge on the break area near them and pick up what they’d ordered earlier that day. On the menu was beer and plenty of workers would have multiple beers over the course of their shift.
These weren’t what you picture when someone says “perpetually drunk and homeless”, but I think a lot of Mercedes were assembled by workers with a perpetual low-level of alcohol on-board.
I worked a summer job at a factory that made box cars. 10x10 or larger sheets of 1/4 inch plate steel lifted on stacks with chain hoists, box cars tacked together, then put on a large rotisserie, so it could be turned as all the seams were welded. Anyhow, At lunch we all went out for shots and beers, and perhaps a doobie or two. While I did not see it, people did get squished. I survived my summer, but I did pickup a nicotine habit that lasted 20 years.
From 1930 through 1970, it was less common but just as tolerated.
MADD did what Prohibition could not.