Twisting a bit the reasoning of the text: perhaps the contrast between yellow vs. others is more meaningful than the contrast between blue vs. others. For a lot of things it’s a big deal if it’s yellow or not: unripe vs. ripe fruit, egg white vs. yolk, gold vs. other metals. Cheese also comes to my mind; we humans have been doing cheese since forever, and aged cheeses are typically yellower (and less likely to spoil).

In the meantime, the distinction between blue and green isn’t too useful in pre-industrial societies - sure, you want to know if the sky is light or dark, but that’s easier to cover by calling it either “white” or “grue”.