As a law enforcement veteran of over 20 years my short answer is - yes. Here is my long answer -
So, by all means, cut police department budgets, but do so to fund other services. I
Ok but the sequence of events is not really by starting to defund police. If you want to say we should invest in other services that are best suited to handle social problems, then great. There is enough money to do that if we stop misusing it.
However, even if at some point some calls for service are answered by other responders, it doesn't mean that the police now have nothing to do. In many depts the volume of calls is so great that low priority calls can take hours to get a response, and the same goes for trying to get the police to investigate anything that is not a serious crime.
IMO, invest in other services first and re-evaluate after some time, how resources match demand.