I had an interest in a bar on Patpong 2 for many years along with friends from Taiwan, and a Thai 'partner'. We never got near to making a profit after all expenses, including those which were unrecorded, were paid. However we were only in it for fun so it was not a problem for us. The experience has lead me to believe making money in this kind of business in Thailand is not easy, to put it mildly.