Defense doesn't break down on the help,

it breaks down on the recovery.

This is so very true.  If you doubt me, watch what happens when the first or pressure defender is beaten. The second or support defender must move to take his place. So far ,so good except the defense is a man down until the beaten defender can recover to either a double team or a supporting role. It's why a defender must not stab or dive in attempting to win or tackle away the ball.  There are cues for when to attempt to tackle the ball.  Do you know what they are?

The answer can be found elsewhere on this site.