Obviously I am aware that not all user actions represent choices, but the hypothetical being proposed was specifically in the context of good established free software alternatives existing. In that context users switching to software with more permissive licenses would imply a choice on the users part. It is reasonable to assume this choice implies the users value something about the other software more than they value what the GPL incumbent has to offer. Of course such a choice could be motivated by many things like newer features, slick website, the author’s marketing, but whatever the case if the license was not sufficient enticement to stay, this feels significant.