What you are not taking into consideration is that we have and want far more luxuries and conveniences than families did in the 60s. If we wanted to go back to the lifestyle of the 60s it could probably still be done on one middle-class income.
It would seem that way, from all the gadgetry many people have today. But - when I look at two close indicator of discretionary spending today and in the 60s it is not so.
Private plane construction peaked I think in the very early 70s, but I'm not going to look it up. Surely the late 60s was a heyday of activity in building GA planes compared to today even if we take the LSA fad into account.
Pleasure boat building also peaked(per capita) in the late 60s. We may in fact build more pleasure boats today, but on a per cap basis the 50-60s and early 70s were great times for trailer boats, and small yachts. I would suspect that campers/motorhomes would show a similar trend.
Hotel and motel construction was booming, Disneyland, Vegas baby, international travel for pleasure, and a host of other activities that were all discretionary seem to have done very well in the late 50s to the early 70s. Some of it was due to the age bubble, but my generation went through that bubble and we don't have the same free-spending potential as they did back then.
One of the main contributors to that decline is the vast and every growing involvement of the various govts in our lives, and pocketbooks. Sure, tax
rates may have been higher for some back then, but actual fed/state total govt spending as a % of GDP was much, much lower. The biggest thing on the table back then was NASAs mission to the moon, and the cold war. To Paraphrase Archie Bunker, paraphrasing Lee Adams: 'Those were the days'.
The country has grown, things are bigger, faster, more advanced and it should be expected that a certain growth in govt would accompany that. No question we couldn't do with the same actual spending that we did in the 60s. But if we look at historical relationship of national GDP to fed spending, the past 8 years has been a disaster, and the coming 5 years will be our doom. It doesn't take a mathematics degree to figure out that exponential spending cannot continue.