I don't know why, is the answer. I'd have thought it was a normal thing to do. When we took out our 1st mortgage in June '74 it was at about 3.5% and we factored in a rise of up to 6.75%/7.5%. Somewhat unfortunately for us the petrol crisis hit and we all know what happened to interest rates!!! Since we'd moved area to buy the house (husband's job) I became unemployed and (with a secure home - we thought) also became pregnant with sprog No.1.
When inflation hit 18% or so and brought subsequent interest rates I'd rather forget, we got on with survival. Hand-washing nappies and bedding, no carpets etc., parents' old blackout curtains. Growing food in every square inch of small garden. We survived. (Made our own beer and wine too - very nice.) TV??
I did warn my offspring, but I don't think they listened. They still seem to afford things I could only dream of (like a car).
You can't put old heads on young shoulders is probably the answer.