Yes, but the prophecies were used to validate the rest of the message. For example, false prophets were to be identified by their future telling not coming true. The message was much more than limited to the knowledge of the individual.
prophecies are analogous to miraculous signs and wonders, they are validation techniques, as you pointed out earlier. There is a context and an explanation surrounding them, they are the point. scientific cosmologically statements are the context, not the point being taught. this is a crucial difference.
in the first, prophecies and signs, they are given an interpretation and explained, we are told that the wine into water at Cana was a miracle. We are told that John is the voice in the wilderness from Isaiah. But nowhere are we told that the earth is spherical, or that the earth revolves around the sun, nor interestingly in the moral and ethical realm, we are never told that slavery is an evil and that Christians ought not to do it.
The framework, the cultural matrix of those Scriptural writers is not being overwritten by God's knowledge. demons are said to cause illnesses, not germs. putting almond branches into drinking water is said to cause mottled goats and sheep, not genetics.
this is the point, what exactly is God telling the writers of Scripture? it certainly is not a dissertation on quantum mechanics, nor is it modern cosmology, nor biology etc.....for in all of these things, they are strictly children of their age, showing absolutely no knowledge of what the world is really like, in the terms of modern science, but rather everything is expressed in naive realistic language of appearances form.
