Apart from those that taught in the International School as teachers (teaching assistants were paid in local money) I didn't meet any expats earning "foreign" wages. They all earned local wages
Yes they risk having nothing on a low wage, but it's a hell of a lot easier to go from a low wage to a low wage than from an extortionately high one to a low (or no) wage.
And when I say extortionate I mean just that. When we lived in Zimbabwe had we converted our joint wage (when I had my better paid job) we would have been earning £187 a month between us. (exH was a teacher in a local school, I worked as a TA in the international school for a while). Both full time wages. No "top-ups"
We lived comfortably on that wage, we didn't have a huge house, in fact it was a tiny 2 bedroom cottage which would probably have fitted in its entirety into my rather modest terraced lounge and dining room that I have now. but we were comfortable (and had we not had a wedding to pay for an a visa and airfares to buy we would have been much better off). We certainly weren't flush, but very comfortable (until I lost my job - but that's an entirely different thread ).
Then a few years ago, when the Zim$ crashed - we used to sent out £40 a month to my exFIL - he lived in his own (large) 3 bedroom house, but that £40 maintained the entire house, and bills, and food, and left money over for him to make his frequent trips to the village
To have paid domestic staff a UK wage would be crazy out there.
I didn't read the original thread - so I have no idea of the details/country being referred to. I am just stating my experiences from the country I lived in where having domestic staff was the norm for both expats and locals alike if they earned anything more than a very low wage.
While many domestic staff coveted the jobs with the expats because of the slightly higher wages, equally many were too scared to take on on because of the job insecurity. At least with someone local that lives there permanently, unless they lost their job and as long as you did the job well you knew you're job was pretty much safe for the long term. No worries about when your employer was going to pack their bags and leave, leaving you out of a job and hoping that if someone came to replace them then they'd take you on.