Interesting topic. Well and truly I think only WG's can answer this. But, imo you can't look at this collectively as everyone's situation is different.
1) You're earning but, in debt.
2) You're earning but, breaking even.
3) You're earning and are above your means (financially independent).
The same will apply to WG's and how they individually approach their finances I guess. From some interactions I've had with WG's I've been told things like:
"I spend as quickly as I earn."
"I have a lot of credit card debt." Yet, said WG would go out regularly to get her nails done, shopping and eating takeaways. Yes, the prerogative is to look good for the job however, her spending was in no means by moderation.
Sometimes when they have a boyfriend abroad... funnily enough he always needs money. Or Sergei is somewhere in the pic lol.
In a lot of cases from personal experience of when they've spoken on finances, I find they burn through their money really quick. Alongside, having really expensive spending habits based on their now 'lavish lifestyle.'
Yes, some I've spoken to are generally quite smart. In which they; invest, save and cut costs wherever possible. As well as having other sources of passive income. So, fair play!
Although, the trade itself will always have availability of men paying for sex. Statistically, 1 in 10 men in the UK pay for sex. Just depends on how popular the girl is, her luck and demographically the client base around. On a really quiet day they could possibly see a client or 2 for short bookings even. All factors to consider.
However, as I said earlier everyone's situation is different. Collectively, based on what's coming (not being political) the industry may feel a hit yet, individually it'll probably differ from WG to WG.