Rampant and not limited to startups. It is amazing to me, as you note, how many people are uncomfortable with it. The opportunity to be part of a company culture and NOT drink is greeted with “phew wow thank you” by more people than you would expect. Lots of people just don’t WANT to drink that much even if they do (officially) drink.
“Startup” culture had unfortunately become a thing- very little critical thought going into what means to have a functional and supportive work environment. Just build the same “culture” every other company does because that is what is “cool” or “accepted” or (wrongly) explains the success of XYZ industry leader.
Where is the after-school special on peer pressure when you need it??? 😊