That would be a different metric. This want to know how many people can’t afford the basics rather than how many people can’t keep up with the relative Joneses.

I'm asking why we shouldn't expect what is considered "the basics" to increase over time, as technology, aggregate wealth, etc. increases? An example to make this obvious: we should probably consider residential indoor plumbing part of "the basics" now, but of course even the richest people wouldn't have had that 500 years ago. In my view, there's no privileged point in history after which we should stop increasing our expectations for quality of life.