The fundamental problem with estimates is that the recipient believes that the estimate will always turn out to be true, which is obviously not correct.
So, why can't we express the upper bound in combination with uncertainty?
Example: "There is a 50% chance that the feature will be delivered within 1 month."
As time progresses confidence starts increasing and we get closer and closer to how much time it actually takes (be that 5 days, 5 months or 5 years). On the day the feature is completed, confidence is 100% because the real delivery date has become known.
So, why can't we express the upper bound in combination with uncertainty?
Example: "There is a 50% chance that the feature will be delivered within 1 month."
As time progresses confidence starts increasing and we get closer and closer to how much time it actually takes (be that 5 days, 5 months or 5 years). On the day the feature is completed, confidence is 100% because the real delivery date has become known.