So why isn't in the Bible. Why didn't any of the early Church fathers write about it, or even later with Augustine and Aquinas.
The fact is that Martin Luther invented it in the early 16th Century as a reason to leave the Church. Even he didn't pretend to have Biblical justification of it. He took advantage of the fact that his "audience" was other excommunicated clergy who wouldn't question him and a populace that was generally illiterate and didn't know if it was scriptural or not.
As has been demonstrated ad nauseum on this and other threads, no Marian beliefs contradict the Bible as long as one is open-minded enough to listen to the Church's theology behind these beliefs.
The bottom line is that "sola scriptura" is a recently invented unbiblical belief that the Church has categorically rejected since the theory was first introduced.
But it is in the Bible, in several places. The most often source quoted is 2 Timothy 3:16-17. Of course, Catholics and followers of Sola Scriptura disagree on the interpretation of that passage, and all others in which we assert the doctrine.
The fact is that Martin Luther invented it in the early 16th Century as a reason to leave the Church. Even he didn't pretend to have Biblical justification of it.
One fundamental truth of Sola Scriptura is that the Bible is inerrant and cannot contradict itself, nor can Tradition contradict the Bible. Luther recognized that the RCC had fully broken away from this idea. All Luther did was formalize an idea that was already true.
Church Fathers must have written about the fundamental ideas just described. I doubt that your Tradition says it is fine to contradict the Bible. Luther and the Reformers saw that the RCC had long been doing this, and in fact continue to do so to this day. Sola Scriptura does not say all Tradition is wrong, it says anything that contradicts the Bible is wrong.
As has been demonstrated ad nauseum on this and other threads, no Marian beliefs contradict the Bible as long as one is open-minded enough to listen to the Church's theology behind these beliefs.
The Reformers believe that the level of open mind you are speaking of SO defies logic and reason that the Marian beliefs, and other dogma and doctrine of the RCC actually do contradict the Bible.