Re. your second bullet, these analyses tend to compare wealth
at the same age. So that one variable should be eliminated.
Then it all comes down to your first bullet, about GDP.
There are two frames I can adopt.
One is to take GDP for granted as a proxy for quality of life and focus on technology and social organization. Maybe we're too focused on computation and not enough on energy production or something else. Maybe there are inefficiencies in social organization -- e.g., monopolies that kill off alternatives, or rent-seekers whose demands distract people from more productive or creative pursuits, or laws that paralyze activity in a sector (e.g. building codes' role in the housing crisis).
Another is to take a step back and question GDP -- which I mean not in some hippy "we need to measure happiness" sense (though maybe that's what it does come down to), but rather in true confusion about how it could measure real wealth. What it seems to measure is roughly aggregate price (which is some kind of monetary artifact), multiplied by the number of transactions that a person engaged in, in a year. How does that measure the value of what they've been able to accumulate?
I get your real point though, which is not really to insist on GDP per-se, but to say that somehow society needs to produce more real wealth, however that would be appropriately measured.