The guys over at Bureau have posted a short background on the interesting history of the Engineered Garments workshirt:
Daiki took the design from a shirt that originated in the 1920s by Big Yank. He introduced it in spring 2000 in Japan and then started to sell it in the U.S. for Fall 2004. Post Overalls actually had this shirt in their collection in the early 1990s but i think it is fair to say that it is the EG one that has had the recent impact.
They really did popularize the design. Side note: some Big Yank items can fetch quite a bit of money in the vintage circles.