This is one reason PI's exist. They will work on a person's behalf without a criminal complaint. Even if the police have one, they may still be ordered to ignore it. They may not care either. It is no surprise that they tend to focus on arrests that net them the most money as well.
You bring up some very valid points. If I could've afforded it when the situation was thick, I may have hired one. I see you are a private investigator! That must be very rewarding! Have you ever taken cases like this?
I have not but I would welcome helping a friend if the situation ever happened to them. As PI's we are basically immune to stalking laws, so we can definitely help out in situations when someone is being gang stalked or intimidated. Yes, it would be expensive to hire a PI out of the blue, but having one in your local network of friends helps. :) The main "problem" in that regard though is that PI's are licensed by state, so I couldn't help much unless someone was in Virginia.