Copyrighted works, on the other hand, don't prevent anyone from creating their own works.
Yes, they do. A person may be a good creator of characters, of settings, of situations, and of dialogues, and having the four abilities, produce a full original novel. Another person might be good at three, two or one of the four, and therefore unable to exercise his creativity except by means of appropriating respectively one, two or three of those from another artist.
Case in point: fanfic. I read a lot of fanfic, some of which better than the original. And why is it better? Because while the original author was good at, say, two of the above four, he wasn't very good at the other two, while the fanfic author complements this weakness, the end result being a fully realized work of art that wouldn't exist otherwise.
Under your scenario however, the fanfic author is in the wrong "just because", no matter how much this harms other artists, and the cultural development of a society as a whole.
How about forcing these descendents to donate their parents' assets to the public domain, just like copyrighted works?
Your workaround to the question of glyphs show you yourself wouldn't accept the full implications of your conceptual framework. This here is another example, because you actually require this very thing from, among others, house painters. Do you pay monthly royalties to the artist who painted your living room? No? Why? Just because he did a minimalist, one-color private installation? Why is this relevant?
And how about the engineer who projected the road over which that person you photographed the other day stood? Did you get a license to make copies of his artistic project which you unconsciously appropriated in your own artistic endeavors?
The silliness you think you're seeing in the above examples is the exact same silliness those who oppose copyright see in the arguments of copyright defenders. And the arguments you use against these examples are also the arguments copyright opposers use. And any difference you'd pretend to find between these positions, thinking your own reasonable, and that of copyright opposers unreasonable, is an arbitrary line drawn in the sand with blurry edges, no more and no less.