Lu Li's proposal would violate the interests of many in power in the Lu Family. If Lu Zhengyang had to promote the mechanism without anyone supporting him, he would be faced with unprecedented difficulties.
When a Family Patriarch had to go against all the other patriarchs, this Family Patriarch might be impeached by others and even… be forced down by the Hall of Patriarchs.
Hall of Patriarchs, regardless of the family, enjoyed the right to force a Family Patriarch to step down when half of the patriarchs reached a consensus!
Usually, a Family Patriarch would not publish a rule by force, risking offending most of the patriarchs.
Someone might have thought about Lu Li's proposal before. However, to implement it would be too hard. Therefore, the proposal never became a reality.