It'll click, just a question of when, and how many players she can trust to work the plan when the season starts.
That right there is the thing. And it may not be lack of trust on the part of players, but a natural reversion to the familiar if the going suddenly gets rough. That's what happens a lot to natural athletes. They can practice new things, but until they've practiced them and done enough repetitions to completely override the unthinking instincts they'd defaulted to in the past, there's always the risk that they'll revert to old habits to get through tight spots or extreme fatigue.
I think this is exactly what Kim anticipates early on, which is why she keeps preaching patience to everyone. It takes a LOT -- and by a lot I mean an ish-load -- of repetitions of very specific simultaneous movements and accompanying thought to overcome deeply-ingrained longtime habits. The easiest thing in the world for an athlete to do is to do the same routines they've been doing since they were 10 years old.
I don't envy Kim's task of retraining all those minds and bodies, but if it can be done at all, I believe she can make it happen. But it's definitely going to take some time. It's a lot.