And the king stood by the pillar and made a covenant before YHWH, to walk after YHWH and to keep his commandments...and all the people joined in the covenant.
2 Kings 23:3

A leader needs the buy-in of his subordinates--or at least of his lieutenants--in order to make any real change. Without it, he will never be able to break free of the mistakes of his predecessors. Unfortunately, their agreement in this case seems to have been a farce since they all turned their back on this covenant the moment he died.