I’m not sure where would fit the bill
Aus and NZ have high difficulty with housing availability, G7 is declining, U.K. still in top ten apparently in 2050 but France out and Italy dropping from top 20 (iirc on that last one)
BRICS going up the chart so any of those will be wealthier over time, whether it is easier for all income levels of population idk
Maybe a Scandinavian country, tax is heavy though and other rich countries just don’t let everyone in
This is the median age list I reckon most people on here would scroll a fair bit past first section, Ireland maybe? It’s a bit younger but U.K. isn’t actually that pronounced and you get there before many Scandinavian and other EU countries.
https://en.m.wikipedia.org/wiki/List_of_countries_by_median_age
There may be somewhere, I’m not sure if I’ve missed one that stands out as particularly good