Sure, and I never said there haven't been. But that's not what happened with Jon in issue 5.
Within the confines of whatever story you're thinking of where they tell Clark he's gonna be a hero (and they don't erase his mind after), it's largely irrelevant to his story that they've told him. And it doesn't explicitly present itself as them readying him to be who he's going to be. It comes off more like them giving him a fun sneak peek and thank you for what he'll do and be. It remains a footnote. But with Jon they're thanking him, yes, but they're also giving him a mission/objective, and they're directly providing him with the tools to do it. They're flat out just asking him to bring the philosophical ideals he learns in the 31st century to the present day to ensure their bright future.