I don't agree with legalising psychoactive drugs, there's a slew of evidence that in many people (especially teenagers) they can exacerbate mental health problems. Also, alcohol, cigarettes & fuel are all legal but all have black market availability through organised crime.
I agree with a pp that a percentage of people would steer clear with better support/education of the effect and consequence of drugs. I am stunned how open drug use is now and aware that weed was turned a blind eye to in prisons because it made most of it's users more manageable. (I think if a few young lads took a good look at what was left of that Range Rover on the Piccadilly line a couple of days ago they might not drive at stupid speeds - a few, not all. Young lads brains are wired for risk taking till their twenties). Peer pressure and social acceptability drove the tobacco and alcohol industry and both those are going through major adjustments thanks to better education and less acceptance of their health effects.
I agree that there needs to be more effective policing, greater numbers, and more community involvement. Many more people have lost trust in the police than when I was young.
I despise the 'I blame the government' line, I used it when I was five but not since. Get involved in government if you don't like what's happening, find out who your MP's & councillors are, join a political party or a community group or a church/mosque/gudwara (gudwaras offer a meal to people in need, many churches & mosques do great work in their communities), use your vote. Get a job in the civil service, become a journalist, join the police, bring up your children to respect others and to care and to contribute not destroy.
That poor mum cracked her door open to see what was going on, I've done it myself if I hear something outside, I've offered help to people in trouble (more fool me). Sometimes we've had half the neighbours out looking out for each other because fortunately we have a good community, though if the town planners have their way that could all change very quickly. My heart goes out to her.