I enjoy your posts but your recollections of past interest rates seem a little off in places. I can remember vividly they were 17% in the late 1980's because I got caught, loaded to the hilt and lost money. The builder had gone bust so it took an extra year to complete. The market turned[plunged] just before it went on the market. I was borrowing money from my family to cover the interest and I sold for 20% less than the target. My biggest regret, which still eats away at me to this day, is that I had a dog from the pound that wasn't too well house trained and she crapped on the new carpets twice in a row. I flipped and took her to the vet and had her put down because I wasn't thinking straight under the pressure. It was 30 years ago and i'm still hoping for a time machine to correct that crazy decision.
Surely they were much lower in the 1970's but still astronomical compared to now.
Here's the link for the standard home variable interest rates for 1959 to 2017 that I have for reference.