I worked places that:
1) have a strict no alcohol policy
2) are OK if you go out for lunch and have a beer (they did have a policy that you couldn’t charge alcohol to your expense account or the company)
3) allow you to drink at your desk (it was a small company, and they did have to carry extra insurance—which gets to my point below)
IMHO, bans on alcohol at work have less to do with productivity, and more to do with liability. In other words—blame the lawyers.
Coors brewery employees used to be allowed to have beer at lunch. They stopped that policy years ago.
I spent 30 years working for this electronic manufacturer that now makes ink. Back in the day the field offices would open the liquor cabinet at 3:30 on Friday. Across the country in Cupertino the gates would swing shut. A semi with a flatbed trailer for the band and the truck with taps on both sides on Fridays. It was like watching “Bewitched”, Sam, make it a double. Then the lawyers moved in.