Key thing about the SG's brief is that while it asks SCOTUS to lower the standard and remand the case, it does nothing to suggest what a lower standard should be, save only to leave existing law alone. In a context where everything is evaluated based on principles (even activist judges give some kind of legal justification), this kind of request will at best give the plaintiff a dirty look.
I don't see how this "hey, just sweep it under the rug" brief is going to have any impact on SCOTUS.