Why did the removal of Saddam husseins regime fail to bring peace to Iraq?

The removal of Saddam Hussein's regime in 2003 led to a power vacuum that exacerbated existing sectarian tensions between Sunni and Shia groups, resulting in widespread violence and instability. The lack of a comprehensive post-war reconstruction plan and insufficient security measures allowed insurgent groups to flourish, further complicating the situation. Additionally, disbanding the Iraqi army and excluding Baath Party members from political participation fueled resentment and unrest. As a result, instead of peace, Iraq plunged into a protracted conflict marked by sectarian strife and the rise of extremist factions.