That scene is slowly dying. The Monger Mecca 'Walking Street' is slowly being overtaken by restaurants, ice cream shops and clothes/sports shops.
Walking Street is a tourist attraction, most of the bars and massage parlours are in the soi's. Probably thousands. The entire city is built on prostitution. The government is trying to change the image and makes a show of it every now and then, but there is too much money involved, especially for the police.
And then there's still Nana Plaza and Soi Cowboy and BoyzTown in Bangkok and even the touristy Patpong. And that's excluding all the massage parlours, soap houses, brothels and whatever else. A lot of Japanese and Koreans are now in this market.
Prostitution still accounts for a 'significant' amount of the national GDP, and those incomes support many families in the rural and poorer parts of the country. Thailand has developed a lot, but outside of the major cities, and even in the major cities, there is a still a lot of poverty and wages are generally still low.
Social media has also made prostitution and freelancing far more accessible and easier than it was before in contacting and getting clients, and the numbers are increasing as a result of this. Not saying it's good or bad, just the way it is.
And now with the COVID-19 situation and its impact on bars and the rising unemployment in other sectors, even more are now using social media and 'dating apps' to get clients or even going to the streets instead of the bars they used to work in.
And of course the biggest users of prostitutes are local Thais.
For what it's worth, mongering is not for me, but people are free to do what they want in this aspect of their lives. Though it may be hard for some prudes and white knighters to understand.