My family tree changed the day my dad became a follower of Jesus Christ. I have no doubt about it. The legacy given me by my father is different than the one he received from his dad.
The same thing seems to happen here in 1 kings 15 when Asa reigns. He is 3 generations removed from David. The Nation has been divided. Both parts are slipping deeper and deeper into idolitry. Yet here Asa makes strong advances towards a resurgence of true worship. He removes idols and gets the perverts (the ones practicing a hyper-sexual form of worship dedicated to false gods). He even removes his grandmother from being the queen mother because of her idolitry and cuts her obscene idol into pieces and has it burnt.
The only thing he doesn’t do is remove the alters at the high places.
Application: we are not destined to repeat the sins of our fathers. Each person is responsible for their own relationship with the Lord.