Because Vietnam was mostly a Guerrilla war, the DOD felt that body count was much more important than holding ground. Because the enemy was highly mobile and didn't seek to take ground, but just kill their enemy, we decided that we should do much the same. So we sought out the enemy wherever they were and we won pretty much every battle. But we still lost the war.In Vietnam, we would fight and die to take ground...and then leave it for the enemy to move back in.
In a war, you capture and hold real estate. You make it yours...not theirs. You keep advancing until you own it all. That's when you win.