When all is going smoothly, we don't feel as much of a need to speak to Hashem and request His help. Sorta like a wealthy person rarely feels the need to ask Hashem to give him parnassa as often as a poor person does. But the reality is, that BOTH are just as dependant on His chesed every second, and at any point the cheshbon could switch.
Our sudden weakness and vulnerability now, remind us to turn to Hashem. "SAVE ME, I don't want to fall!!!" Davka during Elul Hashem wants to hear this more than any other time of the year.