Ken, you’re the bloke around here who knows where all the economics statistics are buried.
So, this idea that in the 70s (and to make it fun, let’s add the 50s, 60s and 80s to it) people could live a full life and raise a family on just the one income.
It occurs that there’s a way to test this. In order to calculate inflation ONS (and if we can find it, Commerce Dept in the US) monitors a bundle of consumer goods. That bundle changes over time as the things which people buy changes over time.
Thus we can use this the other way around. We can examine the consumer bundle for a year in order to get an idea of what the typical lifestyle bought.
For example, at some point between the 50s and 90s ONS will have added a foreign holiday to that standard bundle of prices they monitor. At some point turnips (maybe, depends upon the level of detail, but the weighting of root vegetables will have changed at least) will have dropped off.
So, is there some place where we can see what is in the consumer bundle being monitored in any one year? Easily that is?