The state provides functions which are utterly essential.  Anarchist groups are very naive in believing that we could survive without states, states provide a countless functions that would not exist otherwise. Things like the fire service would be very hard to organise as a community, it is likely that that very few people would volunteer to perform such a dangerous job. There are many vital services that require economies of scale to exist in order to provide the specialized services. This means that something larger than a local community is needed to provide it. For example communities could provide basic healthcare but could they provide the cutting edge research necessary to improve it, and then the expensive treatments to be able to take advantage of that research?  Legal systems are dependent on the state for their existence, without a centralised system of law and a state to appoint judges and organise and fund courts and the police. Under anarchy law and order is likely to look a lot more like mob justice. Without any sort of police force or judiciary it would be highly likely that a community would be able to prevent crime.