> That ends up having a huge impact when inflation and interest rates drop.
How so? The chart in question is for 30 year fixed rate mortgages. You're going to be making the same payment every month regardless of what direction interest rates move.
The mortgage income tax deduction means paying interest comes at a discount, paying principal doesn’t so the effective nominal payment increases over time. However, when inflation is high after 10 years the mortgage becomes trivial to pay. That dramatically increases housing affordability over a lifetime. Making a stretch purchase becomes reasonable, but if inflation is very low making the same nominal payment becomes less affordable every month.
Worse insurance and property taxes are indexed to value and don’t care about inflation. Further people can’t make the same down payment when property values increase. Identical down payments at different interest rates don’t lower monthly payments equally, and at ultra low interest rates their not even a good investment.
How so? The chart in question is for 30 year fixed rate mortgages. You're going to be making the same payment every month regardless of what direction interest rates move.