[Scion9066]

At least in the US, having intellectual property interests isn't about authors having control over every aspect of their works in a moral sense but the public benefiting from the investment in and creation of new works through a limited-time monopoly (from the constitution): "To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."

If you aren't selling them or otherwise making them available to the public, why should the public/government give you any extra control over them in the legal system?

[ToValueFunfetti]

Let's say you're Pablo Picasso and you have a sketchbook from your early years. You get very successful and suddenly the public wants to see your sketchbook. You want to sell the book, but the law says you don't own the rights because you didn't sell it X years ago. So you just keep it, and the public doesn't benefit.

Alternatively, the law compels you to give it away. Little Bobby Picasso, your five-year-old, brings home some stick figures that they drew in kindergarten. In order to be compliant with the law, you now have to give that drawing to the public after X years, along with thousands of others. Presumably also the photos you took of Bobby's first day of school, the song you made up in the shower that morning, and the bedtime story you improvised that night, as they are creative works as well.

[Scion9066]

In the Picasso example, if the you weren't selling your sketches before, then the potential copyright rights were likely not the incentive needed to create the work in the first place, practicing your craft was. Also, just because you don't have a copyright doesn't mean you can't sell it. In this use it or lose it hypothetical system of copyright, it just means that you can't prevent others from using and building off that work. I'll also note that even actual modern copyright treats unpublished works differently than published ones. In the context of the article about live-service games, your sketchbook example would be more like an unpublished game like 0x10c. I'll agree that there might be reasons to still treat published works differently than unpublished ones.

In your second example, again it would be about extra exclusivity rights you get from copyright, not anything you necessarily need to do for every slightly creative act you're involved in. If you were never going to assert copyright on those, why should there need to be copyright protections provided by the public?

In general, the way I was mainly thinking of this kind of potential requirement was for things that have already been distributed to the public but then no longer supported/sold. I see things being made part of the culture by being released but then becoming totally unavailable to be one of the worst things that can happen to creative works when we now have the technology and capability to preserve everything.