WHY ONLY 72 HOURS?

WHY ONLY 72 HOURS? Both political parties have on occasion said that they would adopt a “72-hour rule” that would require—unless there is an emergency—that all legislation be posted in final form online at least 72 hours before a floor vote. It hasn’t happened yet. What I wonder is: why shouldn’t there be a much longer period for comment and deliberation—why not at least two weeks? This should appeal to the members because it would strengthen the position that this is a deliberative body.