I believe the costs are high to replace due to when they decide to purchase a piece of equipment that is not the only cost involved.
There is spare parts, training courses and other factors. A replacement pistol might only be $800 alone. They are kept for a long time, need to be rebuilt, someone needs proper training to do so. Parts can be expensive and need to be on hand. This usually negotiated in the contract. $800 turns into $2500.
That's my understanding anyways, may be wrong.
They do need to be replaced. I'll gladly help offset the costs by purchasing one of the old ones.