"All debt is based on a valuation of some sort. Banks arent...

"All debt is based on a valuation of some sort. Banks arent charitable institutions." Nonsense - debt is debt.

If I have a mortgage of $100,000 and my house goes up by $100,000 in value, I still have a $100,000 mortgage. Similarly, if my house value goes down in value by $100,000, I still have a mortgage of $100,000.

What you are saying is that my ability to borrow against my house changes with its value - no-one disputes that. Also, the various financial ratios, etc. would change, e.g. the asset value to borrowing ratio would change dramatically if a shopping centre valuation drops (or rises) significantly.

ppl can make up all kinds of stats and depending on the slant you put on them, they can look very bad or very good. For example, if a property drops in value but the rental stays the same (or even increases), then the yield can dramatically rise (and vice-versa)!