Excellent post!

I want to clarify one item:

To maintain a constant debt ratio you have to retire half the debt each time the STEEM price drops by 50%. ( @smooth )

This should not be taken to mean I am proposing a practice of literally retiring precisely half the debt when the price drops 50%. In some cases this might be impossible (if the decline occurs rapidly for example). It is more intended to give perspective of what is needed to maintain a "safe" debt ratio (or any other ratio) over an extended period.

Conversely it could be read as a warning of what will happen if the price declines 50% and hardly any debt is retired (the debt ratio will almost double, and retiring the same proportion will then require generating almost twice as much STEEM). This is important because 50% declines in risky crypto assets are quite common. The rest of your post does a good job of putting this into the context that there will always be short term fluctuations and a perfectly constant debt ratio over the short term is not a goal.