The US Army has always changed its uniforms every 10 years or so, it seems that every conflict has to have its own "look". Compare the sky blue waist length jacket and wheel cap of the Mexican War with the dark blue sack or frock coat and forage cap of the Civil War. The Spanish War kept the Civil War color scheme but in a different arrangement. In the 1920s the Army adopted an officer's uniform directly inspired by the British, the Navy adopted the 3 button jacket popularized by David Beatty. Black footwear worn with the blue uniforms, when they switched to brown it was brown footwear. The Ike jacket came from the British battle dress and was adopted because it used less material. The Sam Browne belt was dropped in 1942 as an economy measure. Fatigues were developed because they found that trying to have an all purpose uniform for off post, garrison and field was impractical.
One thing they did right, when the various women's services were established the had the Fifth Avenue fashion houses design the women's uniforms so they looked sharp and fitted properly.