Yes this is true and important, but you and the parent poster probably agree. "in the long term" i.e. asymptotically is constrained by "nobody hav[ing] discreti

Yes this is true and important, but you and the parent poster probably agree. "in the long term" i.e. asymptotically is constrained by "nobody hav[ing] discretionary money left", hence the OP's conclusion. Now ROI and asymptotic analysis are both mathematical niceties the belie real world limitations, but that's how people talk.