Oh I agree, I think it's when kids are involved that it becomes alot more difficult as you really have to prioritise spending, but for the most part, there's no reason cutting back on something for a few months in most households wouldn't allow you to buy a different system to the one you currently own.
It's more a matter of priorities and really how much you want something, non of the consoles are particularly prohibitive in pricing. But then I paid out a bit extra for a Panasonic Viera plasma when they were still making the really goods ones and most people thought I was barmy to pay so much for a TV when I could have paid a few hundred quid less and got a crappy LCD which would have been "exactly the same".
When you are dealing with children there are more than money that decides what you buy - educating them about the value of money, building up their expectations for X-mas and birthdays, makeing them do homework instead of games etc. However it seems that the average gamer is 37 years old (PC & console). Their parenting duties can restrict their consummer choices by the same factors as mentioned above, but money should really not be a problem for most 37year olds that want to have gaming as a hobby.