There is a market, there is a demand from clients and they will seek a supplier that will meet his demand. It is the client, the paying customer that will get his needs met by a sex worker that provide the service he wants. If he wants BBJ, anal sex or natural sex or whatever he wants, he will find a service provider that meets his demand. The providers that do not provide the service a client wants will miss out on business. In a competitive market, in an economic meltdown, suppliers will have to do what it takes to fulfil the demand of clients.
The golden rule is that the customer is king and good service will be rewarded, bad service will be punished with a loss of business.