I disagree with this sentiment. People go to a music venue for the music, they go to a bar for the drinks and a resturant for the food.

If the bar had no drinks, it could hardly be called a bar. Similarly, a resturant with no food is hardly a resturant.

In that meantime, where the reason to go there is missing, these are all just rooms with the potential to be something later. The same goes for the music venue; it's just a big room that could be a music venue if there were actual musicians there.

A dive bar is still a place where people pay for drinks, and not for music.

The "open mic" is on Tuesday nights, because nobody goes there then, so there is no harm to the business, and the people who come to have open mic fun might buy drinks.