drinking beer
Matt Robare asks: "Has anyone ever studied productivity gains from decline of 3-martini lunch + other day drinking?"

I don't know of any great papers that look at the specific history of this. It's worth noting that cause and effect can be hard to disentangle.

Drinking at lunch went into decline in the late 1970s and early 1980s at the exact same time that a number of regulatory changes were implemented that were supposed to make American business less cozy and more competitive.

Whether the change in drinking norms actually caused changes in productivity or were just a product of the larger trends is going to be hard to say. It is true that from what I've read about the history of Prohibition in the 1920s that increased workforce productivity was an important goal of Prohibition's elite supporters.

On the other hand, at least for people in nonroutine jobs, there's some evidence that moderate alcohol consumption could be beneficial. Here's Andrew Jarosz, Gregory Colflesh, and Jennifer Wiley in "Uncorking the Muse: Alcohol Intoxication Facilitates Creative Problem Solving":

That alcohol provides a benefit to creative processes has long been assumed by popular culture, but to date has not been tested. The current experiment tested the effects of moderate alcohol intoxication on a common creative problem solving task, the Remote Associates Test (RAT). Individuals were brought to a blood alcohol content of approximately .075, and, after reaching peak intoxication, completed a battery of RAT items. Intoxicated individuals solved more RAT items, in less time, and were more likely to perceive their solutions as the result of a sudden insight. Results are interpreted from an attentional control perspective.

Blood-alcohol content of 0.075 is pretty low in the scheme of things, but there you have it. On the other hand, do not drink during your job interview no matter how much the social context seems to suggest that drinking is appropriate:

Alcohol consumption and cognitive impairment frequently co-occur. We propose that the relationship is so familiar that exposure to alcohol cues primes expectations of cognitive impairment. Across five studies, we find that in the absence of any evidence of reduced cognitive performance, people who hold an alcoholic beverage are perceived to be less intelligent than those who do not, a mistake we term the imbibing idiot bias. In fact, merely priming observers with alcohol cues causes them to judge targets who hold no beverage at all as less intelligent. The bias is not driven by a belief that less intelligent people are more likely to consume alcohol. We find that the bias may be costly in professional settings. Job candidates who ordered wine during an interview held over dinner were viewed as less intelligent and less hireable than candidates who ordered soda. However, prospective candidates believe that ordering wine rather than soda will help them appear more intelligent.

We have plenty of evidence of things like implicit interviewer bias against female candidates in certain situations, or against heavyset people, or against people with "black" names that all appeal to well-known social prejudices. But as far as I know, there is no widespread social stereotype that people who drink a glass of wine with dinner are dumb. In fact, prospective job candidates think ordering wine makes them look smart and sophisticated. But we've all seen drunk people doing dumb stuff, and that association alone is enough to tip the scales.