Throughout history, there have been a number of movements of various types that have influenced the public perception of drinking alcohol, but I suspect you're referring to the decline of drinking during the 1800s. As societies became more industrialized, negative stigmas were applied more liberally to drunkards because industry required a reliable workforce. This encouraged workers to either drink less or drink at times of the day that would cause their work to be affected by the alcohol less. Many areas introduced last-sale times for alcohol to reduce inefficiency at work the following day (and, since then, these regulations have often been strengthened during war-time to greatly encourage efficiency during a war economy - for example, across Britain during WWI and WWII).

Around the same time (early 1800s), a large number of temperance groups spawned around the industrialized world to combat social problems, like urban crime, poverty, and high infant mortality, that were attributed to the overuse of alcohol.

In general, the 1800s saw a significant shift in the general attitude toward drinking on the job (and drinking in general, but less so) from one of acceptance (being tipsy while working on a pre-industrialization farm would have been no big deal, generally) to one of negativity.

Hanson, D. J. Historical evolution of alcohol consumption in society.

Also recommended: Sournia, J. A History of Alcoholism.

Or, are you talking about Mad Men-style drinking in the office? That certainly still exists today in some companies.

He might be referring to stuff that is portrayed in shows like Mad Men (set during the 1960s USA) where the execs have booze in their offices, take long lunches and drink with their clients, etc

What about Churchill? From what I've picked up people still debate if he was an alcoholic or not. Did he drink/was he drunk while making any major decisions during the WW2?