Well I think the issue is that the policing unions form state and national agreements but local governments are left to negotiate on their own. The DOJ (or something at the national level) really needs more oversight when it comes to policing so that we can have collectivized bargaining on both sides. Local councils can't realistically stand up to police unions in a meaningful way since the national charter can drop a ton of money on elections to get troublesome members ousted... Again, another side effect of terrible election finance laws.
The situation with police union contracts in the US is so bad I think it will lead to courts needing to overturn them as they are not in the public interest.