I think time is running out for Kayne/O'Shea as well. If they don't pull it together during the rest of this season, handwriting is on the wall for them. The top three US teams right now in ability and likelihood of pulling off decent skates: Cain-Gribble/LeDuc, Denney/Frazier, and Calalang/Johnson.
Kayne/O'Shea have altered their technique under Sappenfield. Either they will figure it out and improve, or I suspect they'll move to a different coach. Unless and until a team (or two) distances themselves from the rest of the American field, I don't see why Kayne/O'Shea couldn't return to the top.
ETA - I guess any upside to US pairs is that there are finally other US teams that can compete, be selected and legitimately shoot for a top 10 at Worlds this year if Knierims can't pull it together
I think this is one of the reason that the pairs aren't retiring, because they can legitimately look at their American opponents and say, we can compete with those teams! There also aren't any exciting junior teams coming up to push them out. Not that any of them can compete with the best international teams, though.
To me, the Knierims high point will always be the SP at the Team Event at the Olympics where they turned things around for the U.S. and beat several teams they "should" have lost to, e.g., James/Cipres, Yu/Zhang, and Della Monica/Guarisse. That was an amazing feat!