Thats because there was a massive property boom in these years. A once in a 100 year event. Who knows what will happen in the next 30 years. My guess is it will be the worst 30 years for property in the last 100 due to a correction.I don't understand what you wrote. What I do know , if you took out a loan 30 years ago for an investment ppty , you would now own that property fully and not have to worry about interest rates.
2 more things- you could live in it debt free not having to pay any rent , and also have more dispensable income for items such as holidays or other investments.