Whether or not that is true (I have no position on it although I suspect it is a highly subjective matter, Westphalia not withstanding) there has been roughly half a millennium of anti-papist conditioning that makes it highly unlikely that a majority of the protestant flock could truly in deed and heart return to Catholicism.
Protestants don't universally agree on much, but in my experience, they are unified in their contempt for us.
Yes unfortuantely what they have been taught I’ve found generally whoever taught it to them didn’t know a thing about Catholicism. Oh well the ones who have come back and joined normally are shocked at what they’ve been lied to about though.