I will add a little bit more. Prostitution is the oldest profession. It was there when let alone Bollywood even India was not there. There are many reasons It has not only to do with sexually deprived society only. As you said those Arab Sheikh are not sexually deprived they have money and they use it for this purpose. A person who can spend 10000 rupees he can use that money to have a very simple nikah ceremony too and take care of his khurak for ever. So the problem is in human nature some can control their urges others cannot. Some are looking for adventure. Some are looking to satisfy their fetish some are looking for kinky stuff. The devil is in details as to why it all happens.
Indeed Khurak is the problem, but Mirchi bro here is the new thing, even married guys are more into it. Why is that?