Agreed. Another noteworthy observation from her interview at the U.S. championships is she gave Kersee a vote of confidence. When asked about him, she talked about the challenges of starting fresh in a new system, the need for her and Kersee to get to know each other, and adapting to a different environment. That's concerning because she's now been with him for three years. They should be well beyond the initial adjustment phase!
If the Mu-Kersee pairing was going to work, they would have figured it out by now. All those same adjustment factors she mentioned were applicable to her first year with Milton Mallard at Texas A&M, and she thrived in that year. It shouldn't take three years with a coach to figure out what works, especially for someone who was already the best in the world. In the interview, she talked about how much she loves the 400m and how much it helps her in the 800m, so I don't understand why Kersee didn't put her in any 400m races this year.
She should look at her ex, Brandon Miller, as a case study. He didn't progress under Kersee. Since leaving Kersee, Miller has run a PB in each of the last two years and made the Paris Olympic team. She could have done the same and much more!
The other concerning part of her interview from the perspective of someone who wants to see her maximize her potential is she used the word "content" at least three or four times. She's content with where she's at right now. In the big picture, maybe that's ok. She already has gold medals and the U.S. record. We know she's capable of more, but maybe that's enough for her.
Her contentment, along with giving Kersee a vote of confidence, tells me she's probably not going to make a change. I think the only way she might make a change would be if her husband and/or family do an intervention to help her realize she'd be better off with another coach. That, or (less likely) Kersee having enough honesty and humility to approach her and say, "Look, we've tried this for three years, and it's clear it's not working. I only want what's best for you, and I think what's best for you would be to find a coach who specializes in the 800m and form a 800m training group like you had at Texas A&M. Let me help you make this transition."
Without her switching to a new coach, it's hard to be optimistic about her future on the track. Rather than continue getting down about it, I think my new approach for thinking about Mu will be to just appreciate the memories from 2021 and 2022.