Where did I mention "the fault of poor people?"
There are people that struggle with life in general and the reasons are far, far more complex than simply being "poor".
Fairly often it is their choices/struggle(s) that lead to poverty, debt etc.
If you lack education, family support, have drink/drug issues, criminal record, etc then it is likely you will not be able to get or keep a job, and that can stay with you from the cradle to the grave.
And those people are far more likely to have a prepayment meter.