I did some math. Assuming 12x increase in prices as you suggest, starting with $50k and now $600k, 15% interest in the 80’s, and 1.5% today. Also assumes interest rates are steady in both scenarios. Obviously it is preferable to start high with greater odds of declining, vs start low and can only go up.

Total payments over 25 year amortization:

$50k —> $192,125 $600k —> $719,885

So yeah, interest rates don’t explain it. We are paying too damn much up front!