"Poorly educated" is not the same as 'stupid' - it boils down to 'lacks the certificates necessary to walk into a highly-paid job' which could be down to lack of opportunity as much as anything.
Other important factors are the 'floor' of living costs and the capacity to ignore work above a given number of hours in favour of other uses of a WG's time such as education or vacation. Both of those will tend to maintain or push up hourly punting costs and/or reduce total availability of a WG.
Nope, stupid is stupid. We live in a country in which education is free and enforced up until the age of 16, free until 18, and heavily subsidised thereafter.
As for expenses, condoms are free (sexual health clinic), they work from home, advertising is free (AW). The expenses are (or can easily be made) negligible. They also supplement their 'earnings' by not paying tax (correctly) and continuing to claim benefits.
I don't know what you mean about vacations. We all go on holiday, it's irrelevant.