While think of the children is a factor, I think without an ongoing moral panic or any evidence of rising crimes against children it doesn’t have the political base needed to spur action one way or another. The political push for backdooring encryption is coming from law enforcement not concerned parents. No need for Congress to look for wide public buy in to pass something like EARN IT or this, what supporters need is to convince people to not care. And the argument that does that is “nothing to hide, nothing to fear”.