My opinion on a scale of 1-10 is 9+. IMO, he is describing a learning process which has continued to develop and perform according to expectation. Yes, we are learning, we are building a knowledge based on a thesis which has so far proven to be true.
Dr.M. and team are taking carefully planned and chosen steps. They are not risk averse but they are cautious, which takes time and will probably never accelerate passed the current pace. My guess is they predict (some) change, conduct test, record results, compare w/predicted result and move on. My guess is the team are probably 5+ steps in some sequence ahead of what has been published to date.
So, if they are 5+ steps ahead w/results published so far there is very low risk of failing publicly. Hence =confidence. It's the knowledge curve growth that will cause delays, ie...WHAT IF=#, then repeat, prove by method must = sum num, if Y then party, Method of intuitive/informed PRECISION science progression. Very complicated.