Transport helicopters are dangerous. Fly a lot of helicopters and have them do dangerous maneuvers and eventually you'll have a crash. In an actual war you expect to lose helicopters basically constantly. They're buses for the troops, and they're not meant to be particularly survivable.

Hell, we expected to lose basically every A-10 warthog in minutes if the US went to war with the Soviet Union. And helicopters are slower, fly lower, and they're more fragile.

Of course, none of that would've mattered. The idea was that the conventional war would probably only last until the nukes started to fall.