Decriminalisation is all they could do, it's a similar story to cannabis, it's far too complicated and costly to actually legalise it and the truth is that there'll be very few police forces hunting down WGs that employ a driver, but then nobody wants to live in a house next door to an unlicensed brothel with 10 girls and cars coming and going 24 hours a day.
The biggest problem the industry will have to face is as get closer to a cashless society, it's alright if you're a single bloke but how are married men going to explain £150 transactions to "Mucky Rita" every month?