Juergen Hannappel wrote:

....
Of course economic growth in the hird world is still necessary, but in
the developped part the situation is different; and having an economy
whose main interest is growth also in the third world will not work in
the long term.
....

Well, in actuality it isn't so different except in relative starting
points---there are still sizable populations of disadvantaged in every
country of which I am aware and I know of no magic bullet to make those
on the lower rungs to become content to remaining there in
perpetuity....

W/ apologies to Garrison Keeler, your scenario asks for a situation
where ".. all families' incomes are above average."