My personal take on interest rates is bases soley on HBD never out performing HIVEPOWER in terms of return. Which is why I currently have it at 13% which I would consider the vary MAX interest rates should ever be.
I personally think HBD should compete with FIAT savings account interest rates only. Give people a reason to move FIAT into HBD.. Bring in fresh money.. That kinda idea.
Arguments for keeping rates so high that I often see is we need to print more HBD cause the supply is too low..
In truth.. NO we don't.. We have systems to generate more HBD in large amounts if need be, it's called Hive to HBD conversions. We also have HBD to HIVE conversions. Then we also have posts minting more HBD every day as well has almost 3 MILLION a year in DHF payouts (granted most of that is actually hbdstablizer which a majority just goes back to the DHF)
So I'm very much in agreement that 20% interest rate is not doing any good for the chain and like you said it evidently isn't doing anything bad either, the market simply doesn't care cause there is no market for HBD or HIVE in general. We're just coasting along riding bitcoin waves with an overall slight downward trend. We tend to lose more on the downturn than gain on upturns.
Anything between 5-10% with 13% being the max I'd ever set 'feels' right to me.
If the rate did start coming down slowly I'd likely progressively signal lower rates down until I was set to about 6% or so.
The hardest part about getting rates to change is the fact that only the top 20+1backup are considered in interest rate calcs. There was a period a month or so ago where the rate was changing form 20% to 19% ever other block or so depending on which backup witness was selected.
Making large movements in concensus witnesses is not easy, easier than before with ranks 18-23 being relatively thin margins, but most people just got 20% yolo it's fine without any significant thought.