It's been there since day one. What, you thought early era SF used accurate science? No, they used made-up rules based on whether they could tell a good story.

Science fiction usually doesn't conform to how the world actually works in the same way pornography usually doesn't conform to the way sexual relationships work. They are both there to tell titillating stories, not describe reality.

I believe people use the word “hard” to differentiate more scientifically rigorous scifi. I’m not well-versed enough to know when that started being a term, or what the status quo was before it was a term.

Interestingly there’s also “high” fantasy to differentiate between earth like and non earth like subject worlds, and then even “historical fiction” to describe books that try to be faithful to some degree to some historical time period on earth.

Anyway, this is all to say maybe “how far science-fiction has fallen” might be a narrow interpretation of what’s been happening to fiction in general over the past 75 years. More options than ever, maybe…

I suggest you rewatch star trek. Plot and complexity wise, they are basically childrend stories plus technobable.