You obviously haven't been out with very extroverted people before. People can be very suggestible, I think it's probably possible to create a space where people dance without alcohol or anything else.
-Bouncers often compulsively search you in order to make sure you don't bring extra alcohol inside
-Prices are at a ridiculous premium, typically to profit from the artificial scarcity but also in order to discourage and punish drunken behavior
-Loud party music galore
What exactly is missing?
No club is trying to discourage patrons to have drinks.
Also, some people like conversation. You can't have that at a nightclub
In many clubs there are also areas (usually smoking ones, but also backrooms, lounge areas, and so on) where the sound is muted and conversations (and other things) easily take place.