Police have unions (They function as professional organizations, but legally they are labor unions) largely to block legal changes like this. To defeat them, you'd need to somehow pass legislation on the state and federal level that mortally undermines the power of all labor unions in the USA. This would have knock-on effects for all US workers, as unions fight for and uphold labor protections that benefit those outside their ranks. For instance, two day weekends and 40 hour work weeks.
It seems clear to me that ending QE - Which is merely a judicial policy, it's not even law - Is by far the more potent, simple, and safe avenue of attack. But I'm interested in your thoughts on the above proverbial gun that police unions hold to the head of every US laborer.
How would you strip police unions of their pensions without also destroying the savings of every other labor union in the US? Dissolving labor rights is not the right way to fight an anti-labor force, it's very "fighting fire with fire".