Here’s a chart from Knight Frank’s 2019 Global Affordability Monitor that I think you’ll find interesting:

It compares real home price growth and real household income growth (after tax) over the last 5 years for 32 world cities. The bolded percentages represent the former and the non-bolded percentages represent the latter.

Consider the variations here.

Amsterdam saw a real home price change of 63.6%, but a household income change of only 4.4% (although the circle looks to be in the wrong spot if this number is correct).

Moscow, on the other hand, saw flat home prices (0.1%) and a 22.7% increase in household income.

Though San Francisco is the star in terms of income growth.

Sao Paulo, unfortunately, saw a dramatic decline in both home prices and incomes. It’s in the bottom left corner.

When I look at this chart, I don’t see a strong correlation between household incomes and home prices. And the proportions of the chart tell you that the y-axis is moving more than the x-axis.

But if the top number exceeds the bottom number, then you could come to the conclusion that housing affordability has gotten worse over the last 5 years.