The chassidish method works for two main reasons:
1) They start the boys at about the same age as the girls. So, they don’t have the litvish age gap problem of boys starting at 22-23 & girls starting at 18-19.
2) The parents do much more checking & before letting a shidduch even begin – are comfortable with the couple getting engaged.
The litvish system is set up differently & to change it would be difficult.