Dahn's research is so well respected because he was incredibly good and thorough in measuring tiny amounts of heat and voltage changes in batteries so that you could trace their degradation over a much smaller number of cycles, then try them out at longer scales. Tesla has been funding much of his lab. There are very few people who can do this kind of research outside his lab, and IMO he's a wizard who will end up with a Nobel if he makes a few more big contributions.
The bottom line is that the only way to really tell if a battery will last a year or a decade is to watch it for a year or a decade. No amount of technology lets you forecast the future with perfect accuracy, and battery longevity testing takes time. That's the only reason we don't have a million mile battery.
That would be a good argument if batteries had been stuck for decades at a much lower limit. But the fact is their lifetime has been steadily increasing, and will reach a million miles within a few years at most.
A 1 million mile battery is kinda like fusion. Once it happens there is no going back so I don't think that failing to solve this problem is a blow to EVs.
I don't know whether to believe this, but he has the motive, opportunity, and is definitely present at the crime scene.
One could equally argue that the fact we don't have a million mile battery already suggests that there may be intractible problems to solve.