Based on this comment it's not clear how much experience you have with public sector unions generally or LEO contract negotiations specifically, or how public sector pensions typically work. Barring conviction of a crime (and sometimes even in spite of conviction, depending on the offense), your pension is generally set based on your hire date, and is a percentage of your salary based on the average over some period of time (last 3 years is pretty common). About half the time these pensions are exempt from municipal bankruptcies. It would take legislation to dismantle these pension systems that would almost certainly be litigated and spend years in court, during which time they would still have to be paid out.
They're not putting their financial future at risk.