Of course it is possible, then again, we might not be obliged to believe it. There's always that possibility (which is usually not considered), although once one convinces themself the conclusion is actually a Catholic truth, then it becomes self obligatory. Once that happens, there's usually (not always) no possibility of ever turning back. Such is the nature of sedeism.
Whether the conclusion is right or wrong is in reality altogether irrelevant, the quote from saint Francis that you posted was certainly right, it is up to the Church and nobody else.

In the end, both sede and R&R do not follow the abominations of conciliar popes, the dividing difference between them is that R&R have no reason to add the deciding of the popes' status into their faith. It is because this is not a part of R&R's faith that  causes the sedes to separate themselves from R&R.