Prostitution is legal in several rural counties in Nevada, but only in the form of "brothels". Escorting outside the brothels is still illegal across the entire state of Nevada. So one of the points that I'm making is that if a state like Nevada cannot legalize prostitution statewide, do you really believe that prostitution will ever be legalized in other parts of the good ole' USA? Nope, I highly doubt that will ever happen! I also believe that the Nevada brothels would be history, if those rural counties where they are legal had other source to replace the revenue that those brothels generate through taxes, licenses, and tons of other fees.
Having gotten my start in the hobby many years ago at the Nevada brothels, I've had the opportunity to see first hand how their legal system works and if by chance other states do adopt some form of legalized prostitution, heaven forbid if they use the Nevada brothel model! The only positive aspects are that the ladies are tested regularly for STDs/HIV and you don't have to worry about your physical safety.
...but to answer the OP's hypothetical question ...I don't think the way that the providers and hobbyist conduct business will change too much if things were legal (preferably decriminalized). Although, it would be less stressful for all, since we would not have to worry about LE and sting operations targeting our hobby. It should also make the hobby safer for all and perhaps LE will be able to concentrate on reducing real crime.