Yes, this is precisely what I speculated when people were skeptical about how +Vigano became Traditional after all those years in the Conciliar hierarchy.
After he went into hiding and he was no longer publicly offering Mass, he took advantage of the Motu and started offering the Tridentine Mass, and the Mass converted him, the Mass which is the school of Traditional doctrine and thinking and sensus Catholicus. This Tridentine Mass speaks more directly to people and more sublimely about the truths of our faith than any Papal Encyclical ever could.
+Vigano's conversion to Tradition through the Mass (and it has probably been the case for numerous Motu priests and many Motu laity) is probably exactly why Bergoglio cancelled it.