I think there is another alternative option that you may not be fully considering. I believe (without any facts to back me up) that Disney and runDisney have several scenarios sketched out, perhaps even in great detail. These scenarios would range from complete cancellation to almost business as usual, with an option or two or three in between. The question then is when to pull the trigger on a final option. It's an everyday life problem for everyone, called by Economists "decision making under uncertainty". That is, the best decision as of today may well turn out in retrospect to be a poor decision based on later facts. So if the future may lend itself to greater clarity (less variation), then a prudent action may be to wait absolutely as long as possible.
Now that's all good and theoretical, but the issue for all of us on these boards is that "as long as possible" means different things to different people. Disney worries about logistics and safety (and revenue); we worry about airfare, hotel reservations, dining reservations, training plans, alternative vacations/races, etc. I think, for many of us, our "as long as possible" may be sooner than Disney's; hence the frustration.
Much of this is not a lot different from what you are saying, only that you would like to know the timing and algorithms Disney is using to make their decisions. Unfortunately, even the algorithms may be in flux, and I do not reasonably expect Disney to share them with us.
Or, yet another scenario is that Disney just hasn't set up and labeled the dart board they will use to make their decision.