My claim is that the partial sync problem is intractable unless you can partition your dataset into small topic documents. If this claim is correct, it is not "momentarily correct", it is inevitably correct, i.e., "incapable of being avoided or evaded". If the claim is not correct, I welcome any of the many researchers in this space to correct me!
I understand your claim! Mine is that even if it's correct, it's not "the fatal problem in this category", for the reasons I outlined.