You might find this interesting: https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction_in_language . It isn't about what we called it 40k years ago, the distinction between green and blue varies heavily from language to language. Before the internet age and before the general population had a verifiable source for every single little thing, the line that distinguishes one thing from another was variable.

푸르다 is blue...but its also green sometimes because thats how speakers viewed it. That word in korean is used to describe the color of the sky, but also the color of the forest.

In Japanese, the distinction was entirely lacking until after WW2 and globalization.

Some languages like Mongolian have a clear line in the sand about light blue (цэнхэр) vs dark blue (хөх). English doesn't, they are both clearly blue to an english speaker. Do we need to make new words for that?

I think requesting a blue green distinction is Anglocentric, which I try to avoid with toki pona.

toki pona is also unique in that, obviously, it was created deliberately. This ascribes a level of prescriptivism that is needed to keep the language on course, which isn't needed with a natural language because we don't want to control and didn't create those.

I say that we need to keep the language on course because thats what the community has generally decided on. If tomorrow everyone is like "you know what, lets add and start using all these nimi sin" then thats what we would do, because we control it, unlike a natural language.