FK, have you ever heard of the concept of “sporoi”? The word means “seeds” and the Fathers spoke of flashes of the revelation of God to mankind among, generally, pre-Christian pagans as “sporoi”. These seeds of The Truth are seen through history and throughout the world. Hinduism and Buddhism are full of them. Since we don't and can't know where the Spirit goes, it seems to me we ought not to make such blanket statements as yours above.
I've heard of it and ran across it when I did a little reading on Hinduism. But I would never compare it to the Biblical concept of "God-breathed". In my limited reading, I found no claim of any kind that sporoi could come close to passing the test in 2 Tim. 3:16-17. For one thing, that verse says "all scripture" and I found no claim that sporoi ever encompass all scripture of any particular faith. I don't see how snippets here and there could compare to a complete and self-contained belief system.