Throughout history many prostitutes have lived in conditions of actual or near slavery.
English country girls used to routinely be lured to Belgium or France with offers of legitimate employment and then forced into prostitution. Meanwhile, French girls were lured to London under similar pretexts and treated the same on arrival.
There is very little new under the sun.
Victorian reformers had rescue missions for prostitutes who wanted to leave. Increased economic opportunity gave poor girls other options. Law enforcement made it more difficult for entrapment to occur. Prostitution wasn't eliminated but at least it was voluntary.
The British open borders policy has brought back an evil - involuntary prostitution, sex slavery - that was mostly wiped out a century ago in that nation.
Mrs VS
Asians and hispanics suffer the same fate in the good ole USA.