You’d assume so, but this is in fact false. https://en.m.wikipedia.org/wiki/Blue–green_distinction_in_la...

That doesn't really support your contention. The color naming debate underlying the entire discussion is primarily focused on basic color terminology, for which colors that are merely allusions to a physical object (e.g., turquoise, gold, lavender) are excluded. But that doesn't tell you what terminology people will actually reach for in description. Japanese, for example, uses "ao" to refer to essentially the entire blue/green spectrum, but "midori" (lit. "leaf") is used to green, increasingly to the exclusion of "ao" in modern Japanese (side note: this is literally an example, explicitly mentioned in your reference, of what the GP is suggesting happens).

As far as I can tell all that articles says is that there are languages that use a single term for green/blue, not that speakers of those languages are incapable of identifying the difference between the colour of a leaf and the color of the sky. I can distinguish between the colour of the sky and the colour of blueberries (and treat them as categories of colours) even if I use the same word "blue" for both.