So, I saw that this question was closed as a duplicate of this question, but I don't think it should be. The second question is "why are the cockpits of Soviet aircraft painted blue-green", while the first question (the one closed as a duplicate) was "why are the cockpits of Soviet and Western aircraft painted different colors". The answers for them should be different, since the answer for the first question should address why, if the Soviets found that blue-green was objectively the best color to paint aircraft, the didn't West copy them.
I don't have the reputation to vote to reopen, and one of the diamond moderators has told me to open a thread on Meta about it after I left a comment and a moderator flag asking to reopen it.