Can you explain me how the math works on this? Because I certainly can't afford 99.9% of the houses/apartments in Sweden.

Let's forget anything crazy. Let's just talk about a 70sqm apartment in Kungsholmen

and of course wealth percentile matters. In fact, I understand that way too well. How do you raise your wealth percentile then? The whole point people are raising is that it's hard to become wealthy in Sweden from income. Actually much harder than in other countries. It might have worked for you in the last 20 or 30 years. Not sure that means it will work for others the same way in the next 30 years.