Are the prostitutes in Australia typically poor immigrant women? Wealthy, powerful women with a broad spectrum of choices do not typically choose prostitution.
See http://www.nswp.org/sites/nswp.org/files/NSWSexIndustryRepor... There are other interesting things including 'Sex workers’ reasons for choosing current workplace' was 'Hours are flexible' and 'the LASH study found no evidence that any of the women had been coerced into working in a brothel'
Street walking prostitutes are generally illegal, and unregistered brothels are illegal.
Check out http://www.scarletalliance.org.au/research/ for more research.
It does seem like it's primarily foreigners who cannot get a job. This seems exploitative. And the article you cite doesn't paint a rosy picture of everything being great with legalised prostitution.
Wealthy, powerful men with a broad spectrum of choices do not typically choose cleaning the toilets at your office.