I was going to present more problems with that pillar of Protestantism, but then I found this article by Jim Atkin and so no reason to re-invent the wheel!
The disintegration of Protestantism into so many competing factions, teaching different doctrines on key theological issues (What kind of faith saves? Is baptism necessary? Needed? Is baptism for infants? Must baptism be by immersion only? Can one lose salvation? How? Can it be gotten back? How? Is the Real Presence true? Are spiritual gifts like tongues and healing for today? For everyone? What about predestination? What about free will? What about church government?) is itself an important indicator of the practical failure of the doctrine of private judgment, and thus the doctrine of sola scriptura.
However, there is a whole set of practical presuppositions that the doctrine of sola scriptura makes, every one of which provides not just an argument against the doctrine, but a fatal blow to it. Sola scriptura simply cannot be God's plan for Christian theology.
Here are his 7 basic problems with it!
1. Requires ability to [print!)
Thus the universal application of sola scriptura presupposes the mass manufacturing of books, and of the Bible in particular.
2. Requires mass distribution of bibles!
Second, besides the printing press, sola scriptura also presupposes the universal distribution of books and of the Bible in particular. For it is no good if enough copies of the Bible exist but they can't be gotten into the hands of the average believer. There thus must be a distribution network capable of delivering affordable copies of the Bible to the average Christian.
3. Requires Christians be able to read!
Third, if the average Christian is going to read the Scriptures and decide for himself what they mean then he obviously must be able to read. Having someone read them to him simply is not sufficient, not only because the person would only be able to do it occasionally (what with a bunch of illiterates to read to), but also because the person needs to be able to go over the passage multiple times, looking at its exact wording and grammatical structure, to be able to quickly flip to other passages bearing on the topic to formulate the different aspects of a doctrine as he is thinking about it, and finally to be able to record his insights so he doesn't forget them and he can keep the evidence straight in his mind. He therefore must be literate and able to read for himself. Thus sola scriptura presupposes universal literacy.
4. Must have scholarly materials available.
He must also have these scholarly support works (commentaries and such) to suggest to him possible alternate interpretations to evaluate, for no one person is going to be able to think of every interpretive option on every passage of Scripture that is relevant to every major Christian doctrine. No Protestant pastor (at least no pastors who are not in extreme anti-intellectual circles) would dream of formulating his views without such support materials, and he thus cannot expect the average Christian to do so either. Indeed! The average Christian is going to need such support materials even more than a trained pastor. Thus sola scriptura also presupposes the possession-not just the existence-of adequate support materials.
5.Need time to study!
Fifth, if the average Christian is to do a thorough study of the Bible for himself, then he obviously must have adequate time in which to do this study. If he is working in the fields or a home (or, later, in the factory) for ten, twelve, fifteen, or eighteen hours a day, he obviously doesn't have time to do this, especially not in addition to the care and raising of his family and his own need to eat and sleep and recreate. Not even a Sunday rest will provide him with the adequate time, for nobody becomes adept in the Bible just by reading the Bible on Sundays-as Protestants stress to their own members when encouraging daily Bible reading. Thus sola scriptura presupposes the universal possession of adequate leisure time in which to make a thorough study the Bible for oneself.
6.Sola scriptura pre supposes universal adequate nutrition
7.Must be skilled in evaluating arguments
that level of critical thinking does not exist in the average, literate, well-nourished, modern college senior, much less the average, illiterate, malnourished, Medieval peasant. This is especially true when it comes to the abstract concepts and truth claims involved in philosophy and theology. Thus sola scriptura also presupposes a high level of universal education in critical thinking skills (a level which does not even exist today).
Christianity survived 1500 years without the doctrine of sola scriptura- 400 of those even without a bible as we know it today! So to my mind it's clear that historically sola scriptura is unsupported!