Question

Why did the old man have no need to build the bridge across the chase

Answer 1

$\huge\underline\mathfrak{Answer :-}$

The old man had already crossed the river. So there was no need for him to repair the broken bridge across the chasm. He could have easily went on to the other side without bothering about who comes next. Without any selfish reasons he repaired the broken bridge for others who would come after him.