I am not completely in agreement with this study. I only read the Atlantic article, I did not read the study so maybe I missed something. From what I have observed, the younger teachers who were on tenure track in universities were always more focused on getting research grants because that is what helped them get tenure. The older ones were more likely to win best teacher awards.
From my just my personal experience of 8 years in grad school I feel like it is just the enthusiasm that some younger teachers show that is infectious and makes you feel like the teacher is good. The older teachers are actually better at drilling down concepts however they were less excited about the material and somehow that transferred to the students as well. Students were more likely to feel bored in their classes. I was a TA and that was a frequent complaint about my advisor but I used to go throw his material and it was fantastic.
That said there was one tenured professor who was an okay teacher but left the teacher survey on the last day of classes, on our desks, on the way out muttering "Write whatever you want, nothing can happen to me."