When did wearing marksmanship badges become the norm?

The Army began using marksmanship qualification badges in 1881 starting with the Marksman Button. That led to a variety of different U.S. Army branch-specific marksmanship badges until 1897 when the Rifle Marksmanship Badges were implemented Army-wide. The U.S. Army's Pistol Marksmanship Badges were implemented ten years later in 1907.

This is what is on Wikipedia:

"The Army began using marksmanship qualification badges in 1881 starting with the Marksman Button. That led to a variety of different U.S. Army branch specific marksmanship badges until 1897 when the Rifle Marksmanship Badges were implemented Army wide. The U.S. Army's Pistol Marksmanship Badges were implemented ten years later in 1907. Clasps were added to the Sharpshooter Marksmanship Badge and Expert Marksmanship Badge to indicate the year(s) a soldier requalified as a sharpshooter or expert. Up to three years were denoted on a single clasp. Upon earning the badge a fourth time, another clasp was added and that new clasp was used to denote up to three additional years of requalification; there was no limit to the number of clasps that could be hung from these badges. In 1915, the U.S. Army changed the design of the Expert Pistol Qualification Badge's pendant by replacing the revolvers with M1911s; this pendant lives on in today's Marine Corps Expert Pistol Qualification Badge. Additionally, the U.S. Army had a short-lived series of Artillery Qualification Badges from 1891 through 1913. In 1921, the pistol and artillery badges were combined into today's Army Marksmanship Qualification Badges through the addition of the Pistol Clasp and Field Artillery Clasp. Prior to 1951, the names of the qualification levels for the current Army Marksmanship Qualification Badges were known as (highest to lowest) expert, sharpshooter or first-class gunner, and marksman or second-class gunner. Also, prior to 1972, the Army Marksmanship Qualification Badges had many different types of weapon qualification clasps. According to The Institute of Heraldry, the following is a list of previously awarded Army Weapon Qualification Clasps:"

I found three pictures of WWII soldiers wearing marksmanship badges - these were just the first three I found and saved when I searched "WWII uniforms marksmanship badges." Most of the results are the new "pinks and greens" though.

It might have something to do with the fact that many of those who served in the two world wars were drafted or were last minute enlistees. These individuals would never have had the opportunity or ever had the desire to wear such accoutrements. It may also be the burgeoning of the "professional soldier" after veitnam played a role in promoting the wear of such things. Just spitting out ideas, but both would make perfect sense.