The M1911A1 was chosen in the first place because of it's high reliability and good results in range tests. The 1911 served faithfully in the trenches of World War I, the European and Pacific theaters of World War II, the forests of the Korean War, and the jungles of the Vietnam War. But the time came when the 1911 had to be replaced. In a world that was becoming more and more reliant on technology, the U.S. had little use for a pistol that had been around since the horse and carriage. The 1911 was replaced by the M9 Beretta as the U.S. sidearm of choice, because the M9 was similar in performance but had a high capacity 15 round magazine, compared to the 7 round capacity of the 1911.

I can't say much about the Luger P08 or the Walther P38, or whether they were inferior to the 1911 or not, because I just don't know about them.