It might be because they get tired of their old names.
Toronto blue jays
names on uniforms
Angels, Athletics, and Astros
The Cleveland Indians.
Yankees, Astros, Expos, Rays
Oakland Athletics
New York Yankees
Baseball team names that start with the letter "A"AngelsAstrosAthletics
Philadelphia Phillies and the Pittsburgh Pirates
San Fransisco Giants and the Texas Rangers
The Florida Marlins and the Tampa Bay Rays.