If you think this is a conflation, perhaps you could explain how and why they shouldn't be?
Most people nowadays are poorer than Mr Darcy in a monetary sense, but probably have a higher standard of living.
The sibling post makes the point that in the past, being wealthy was a much bigger component of this - if you're rich you can afford a doctor (versus none), you can eat when others go hungry, you can afford to travel at all, you can be educated, etc.
As I understand it, standard of living is objective - you can quantify it fairly well. Quality of life is subjective.
Your comment focuses on standard of living issues. But your earlier claim was that these are separate from 'monetary wealth'. I think you would need to specify what 'monetary wealth' is separate from 'standard of living' in order to make a convincing argument.
You'll find this hard to do, because any wealth measurement is either a thing, or an instrument that will get you a fraction of the things other people have. Financial wealth is cashed out in stuff. So cross temporal comparisons are going to involve comparing the stuff two people can command. And the stuff they can command is embedded in the technology and society of their respective times.