> Chicago also ditched it recently I think.

Kind of. The mayor said he was shutting it down for not being effective. And then he went and renewed the contract until just after the DNC convention: https://chicago.suntimes.com/city-hall/2024/02/22/shotspotte...

My read is that they know it does work but they don’t want to continue to use it because statistically the “wrong” people are committing the crimes it’s tipping off.