In the early 80s with high inflation and therefore high mortgage rates, the first years of mortgage payments would be a relatively high percentage of income: it's very front-loaded. However, the debt owed quickly gets deflated away, so over the span of 25 years you're actually paying a much lower percentage of your real income. To take it to the extreme, if inflation was approaching infinity, and mortgage rates were 2% + inflation, your first payment would be 99.9% of the value of the loan, and all subsequent payments would be essentially 0% of your nominal income. Add to that fact that a downpayment went a lot further (if you saved to 50% of your median income, that was 20% down payment of median house), and affordability back even in the worst of the early 80s, while not great, was better than now.