I think CASL lined up consumer expectation with the law. Prior to this time, consumers wanted to have control. They thought that they should only get emails that they've consented to. Now, the law lines up with that. That's really my only way to answer your question.
If it's changed back to opt-out, people will think they have control and they won't. Their spam volumes will go back up and they'll start getting problems. That's the only way I can express my answer.