One theory is that the brick wall backdrop was originally used in vaudeville theaters. Vaudeville was a type of variety show that was popular in the late 19th and early 20th centuries. Vaudeville theaters often had a brick wall backdrop because it was a simple and inexpensive way to create a neutral background for the performers.
Another theory is that the brick wall backdrop was inspired by the speakeasies of the Prohibition era. Speakeasies were illegal bars that operated during the Prohibition era. Many speakeasies had a brick wall backdrop because it helped to create a cozy and intimate atmosphere.
Whatever the origin of the brick wall backdrop, it has become an iconic part of comedy clubs. The brick wall backdrop is a reminder of the history of comedy and the speakeasies of the Prohibition era. It also helps to create a relaxed and intimate atmosphere for comedy shows.