World War 2 and the draft
During World War 2, many big band members were drafted or volunteered to join the war effort. Big bands lost some of their great members, and thus big bands came to an end. Swing music, which was very popular during the war, died out at the end of the war. This happened because swing music was a reminder of the war and many people who were sad about the war tuned out swing or turned it off.
Transportation was difficult
During World War 2, automobile fuel was rationed and made it hard for many traveling big bands to tour, perform, and make a living.
From July 1942 - November 1943, there was a recording ban that prohibited jazz instrumentalist to record. Many big bands were not able to record and thus broke up. Vocalist, however, were able to record during the ban and their music became more popular.
In 1941, a new tax required clubs to pay 20% of their sales in taxes. This caused clubs to hire smaller cheaper bands to be able to stay in business. Swing bands, which were often quite large, lost out on many gigs and were fated to come to an end. A midnight curfew was also enacted and kept people from going out all night to clubs listening to music.
African American jazz musicians had almost always been treat less fairly then whites, especially near the end of the Swing Era. African Americans were tired of getting paid less then whites big swing bands. African Americans created Bebop as an outgrowth against all the racial prejudice and segregation they face. They also wanted to create a music for listening to, not dancing. They wanted their music to be more of...