This is completely false. The standard measurement bars use is called the "pour cost" which is inventory usage(in cost) divided by sales. The pour cost average for a bar is between 18-20%. That's a gross margin of 80 to 82 cents on each dollar a customer spends on drinks. That's a pretty spectacular margin. A well-run bar on a busy night is practically printing cash.

A bud light at a bar is like $12 now at most bars. The case at the gas station across the street is $18. The splash of coke in the $10 well drink that begins with a cup scooped full of nearly free ice must have been about five cents of syrup and one cent of CO2, the pour probably came out of a bottle that costs like $15. Maybe that maxim was true back in the day when people could actually afford to get drunk at bars, but not anymore.

That's an awfully high cost for well liquor. The 'good' well liquor will be about $10 max, and the rotgut can be as low as $4 if you but a couple cases at a time.

I do most of my drinking in high cost environments (NYC + Boston) and that still seems way too high of an estimate.

$12+ for a beer is typically the high end of craft beer, not Bud Light.

I run a restaurant. A regular domestics (bud, miller, coors) run about $1.10 per can/bottle if you get a single case. Busy bars ordering 10 cases at a time will be getting discounts. Unless you're going to the shittiest dive bar in town, a $3 domestic bottle is nearly 200% markup.

Surely domestics have to be cheaper than that from suppliers. My local Total Wine has $0.45 Miller cans.

This is the opposite of true. Not even factoring in the cost of labor and everything else related to having a kitchen.

As someone who spent a LOT of time working in/running professional kitchens in the US (NJ specifically) I would just like to say:

CITATION NEEDED