You're not wrong that for whatever reason sex work isn't a preferred vocational option as it used to be. Hence the sheer number of Brazilian, Romanian and Hungarian WGs in London (compared to, say, French, German or Swedish).
I saw a world class Pole for £30 once and she admitted that she didn't mind working most of the week for a cleaner on a pittance compared to a scuzzy brothel in Stratford. There was another in Crystals Sauna Leyton who I visited whenever she was on, I jokingly wrote a letter to her parents back home to congratulate them on producing such a pair of chebs.
Too much online money too, for the lookers and exhibitionist types, other jobs, greedy pimps, crazy rents, scuzzy punters, but all blamed on Brexit innit, while they flood in from South America and elsewhere.
Poland is one of the few to prosper somewhat from EU membership, I know construction workers that went there for work, pre pandemic so that must have some effect too.
Lots have built that house back home, no mortgage, from earnings here, not just SP,s, construction workers, truck drivers etc, lived on a pittance, saved and spent wisely back home, employing others there while working here, maybe the GF turning tricks too, then off they went back home.
Lots of reasons numbers are dwindling, Brexit is not one of them. I used to see one in Barking, worked as a cleaner on the tube, turned a few tricks, went home comfortable, she is not the only one.
The glory days are long gone