As were the South Vietnamese in 1975. Fighting and dying for their freedom is not in their DNA.
South Koreans fought with us in Vietnam (as did Australia and a few other allies). ROK units were very effective, particularly the ROK Marines. In one instance, they took over ground defense for an American airbase that had come under frequent rocket and sapper attacks from the Viet Cong and North Vietnamese.
While the U.S. unit that previously handled the task stayed close to the base, the ROK Marines launched an aggressive patrolling campaign over a wide area to find and engage the enemy. When they killed some ranking VC, they hung their bodies from trees and put up signs announcing they were now in charge of security in that area. Attacks on the base dropped dramatically in a matter of days.