It is explicitly trying to optimize for measuring/inculcating military performance.
1. West Point does a very good job of selecting for and rewarding the same traits that lead to career success.
2. The most successful military leaders (especially in wartime) become famous, far beyond the most successful doctors or lawyers. 12 of them became US Presidents, but this has been true since ancient times. The guy with the best grades in Harvard Medical School might have a fantastically successful career, but you haven't heard of him.
Unfortunately we still need them for now.