It's been varied, but whenever I've needed to call the police they've gotten to me within 15 to 30 minutes depending on my location and reason. Sorry to hear they haven't helped you at all, I don't know if my city is just better at response times but that's why I say I personally haven't had an issue with them and it's a shame others like your self do.
We need better mental health care in this country for sure and there's definitely a need for a new change of strategies and policies especially surrounding poverty, but as of right now all I can personally rely on is the police. I don't know if you live in America but here if you even so much as punch or push someone by defending yourself, you get fined or charged for assault, and that also includes defending yourself against robberies or home invasions.
I'm all for positive change and even defunding, just as long as there's something I can still rely on for help.