The only reason that was acceptable in WWII was the the horrendous casualties that were being suffered by U.S. troops made it seem not so bad. Today, no one would allow that kind of mortality rate.
Also the aircraft were relatively cheaper and they made lots of prototypes. Lose one today and it may be the only one or maybe one of two.
Certain folks are willing to hang it out on the line even without a terrible hot war going on. It's a mind-set. We had 'true grit' back then. Apparently, we don't now.
Frm. Sect. McNamara is pleased.
/johnny