I think you're making a mistake trying to apply something like Moore's law to a middle class lifestyle. Niche technological advancements don't necessarily translate to higher standards of living. If you're thinking the middle class life will simply scale the way hard drives and TV resolutions do you're in for a big surprise.

I understand that many of the things we think we "need" or want become very relative over time. But if we include basics like needing food, shelter and then add in middle class health care, mobility, security, leisure and luxury, you are talking about an expensive ticket. Yes we have made impressive advancements and maybe someday we'll have things like 100% robotic aggregation/farming and no longer need to think a lot about how we'll get our food. But I don't think the middle class life will simply becoming the default option anytime soon.

What about overpopulation? Increase demand from developing nations for this "middle class"? What about our numerous energy issues? I'm also not sure what your frame of reference is for the past. I must be stuck in the rebound towards an up trend because I know for a fact that a houses were much more affordable for my parents who lived on one carpenters paycheck, even while I make a higher salary after inflation and have the assistance of my spouses income.