Hi CoteDAzur
There's no magic solution. All varieties of legislation address one problem and cause a counter-problem.
The cause of prostitution is male entitlement to sex, male attitudes towards women and their bodies, and women's economic disempowerment caused mostly by basically being a woman.
Women need money + Men "need" sex = Prostitution. Legal approaches only go so far in this equation.
My involvement has spanned a period of approx 20 years with several years away and doing other things but going back to it as mostly a side-line.
Each time returning I have noticed major changes driven by technology, rising immigration levels, the rise of internet porn and many other influences.
The law in the the UK hasn't changed a great deal since partial criminalization was first introduced so I can't credit any changes to that. It seems to work for the UK, establishments get closed down, WGs move on, kurb crawling is illegal but still happens, brothels illegal but still happen etc. The biggest influence to the industry are other laws surrounding immigration and trafficking.
On speaking with WGs about intoducing decriminalization, most are all for it for obvious reasons but if you give it more than a minutes thought you can see there are huge and very problematic ramifications. The saturation of the market, being a magnet for trafficking and sex tourism, and doesn't work in the way it is supposed to RE employment rights etc.
The Nordic model has been most effective on reducing street prostitution, which is a positive result, because street workers are the most vulnerable. When it comes to brothels etc the police know full well there are brothels but they are not camping outside arresting all the blokes because arrests generally occur on informer basis. Prostitution happens under Nordic model and I would take and official stats on the levels with a pinch of salt. Downsides are more pressure on WG to be secretive.
Where Nordic Model wins it for me in making men think twice for their actions, and results in the man being doubly respectful to the WG.
Any hint of misdemeanor, any aggressive text message or abusive phonecall, any punt where the man demands a service he hasn't paid for or even asking for something again that the WG has declined alread, all these disrespectful behaviours are basically bang to rights illegal under NM. The wider implications win it for me too, as it's basically about respect for women.