There are literally hundreds of mainstream social club events out there, with constantly busy dancefloors playing the top 500 plus a bit of disco, pop etc. good for them but not something of interest to the vast majority of people on here or generally people under 30. True, some of the specifically "underplayed" nights have little atmosphere either.
Personally I like a mix of the two 50% mainstream, 50% I've never heard of, mix it up and keep everyone happy, sadly that rarely occurs.
There are a few events though with busy dancefloors, a total mix of ages and little in the way of the top 500. And they are a real treasure.