Dunno if its only stern. I'm sure a lot of people here have purchased when a 'sensible' person if figure you are alluding to wouldn't fall for such temptations. I'm guessing, based on no factual study, that the majority here have a mortgage. Now how many pinballs at exorbitant prices could they buy with the savings in interest had they used their current pinball spending and put it on their mortgage. In my case, once the GBLE hits my shores, that'll make it nine (my collection).
I think we should all collectively admit we are irrational in this hobby. Irrational people are not the smartest people. Also remember continually telling people they are going to fail doesn't make them feel great.