Law enforcement is rarely the answer to complex social problems, though. Increased law enforcement is much more likely to make them worse, because it is so deeply rooted in punishment, control, and protecting the powerful against the powerless. Increasing law enforcement as a way to address the problems associated with sex work invariably makes those problems worse - you don't 'rescue' people from sex work by stealing their money and deporting them, which is what tends to happen every time more restrictive laws are introduced.
No one is suggesting it is the only answer.
But look at drug issues. We know that certain social problems contribute a lot to drug problems, homelessness being one, and also that drug addicts often need help rather than going to prison.
So you get these cities where there is a progressive tendency in governance and they try and solve all these things by decriminalizing, stop prosecuting people they see as vulnerable, reducing what the police can do or just reducing the police altogether.
But it doesn't work. What you get are cities where the areas poor people live are dangerous shit-holes controlled by gangs and drug dealers. And that has a significant effect on the people that live there, and their children - it does not result in an atmosphere that doesn't encourage addiction.
Simple decriminalization of prostitution, even if you offer help, still does not mean that the forces that lead to it will be erased. There will still people coming out of bad environments, there will still be addiction, there will still be people willing to pay for sex, and there will still be people looking to profit out of providing for that market. All you do with decriminalization or even legalization is legitimize the market and make it easier for the bad actors.
It's entirely possible to refrain from criminalizing prostituted women, and put things in place to help them, but to criminalize paying for sex on the side of the punters, and pimps madams and traffickers.