Good question.
That's how my brain is wired. By nature, I am an efficient minimalist: Occam's Razor
As I say what I'm about to say, I want to be clear that as a Lutheran I subscribe to the Lutheran position of Sola Scriptura, that Scripture alone is the Unruled Rule of Christian faith. In other words, Scripture is the highest authority in matters of faith and practice in the Church and the Christian life. And that nothing can be accepted that violates or opposes Scripture, which is the faithful, and received word of God in the Church.
It's important to remember that the Bible itself doesn't exist in a vacuum. It's not as though suddenly, out of the blue, there was this leather-bound book with a self-authenticating authority. The Bible is a collection of texts which were written over a span of centuries by numerous authors, in different locations and under different circumstances. Comprised of two halves, an Old Testament, containing the Torah, the Prophets, and Writings, and of the books that make up these three parts of the Old Testament there was no universal agreement among Jews until the post-Temple Rabbinic period of Judaism. In Christianity, the Old Testament Canon developed in a distinct way from the way it developed in Judaism. As it pertains to the second half of the Bible, the New Testament, it can be broadly split into two categories of writings: Homolegomena, the writings which were near-universally accepted from very early on, and the Antilegomena, or "contested writings" which were debated and discussed for a long time in Christianity.
The evolution of the Bible as a Canon of Sacred Scripture; that is, a unified standard of texts regarded as holy; took place over many centuries. And in a sense, that discussion and debate has continued until today, as there are still disagreements over certain books, which the Protestant churches have generally called "The Apocrypha" since the time of Martin Luther, but which the Western Church has generally designated Deuterocanonical (the distinction between Protocanonical and Deuterocanonical doesn't exist in the Eastern Churches).
The way the Canon of the Bible evolved and developed was chiefly liturgical. Which is to say, it happened in the context of Christian worship. Like our Jewish cousins before us, Christian worship is historically liturgical, following a form, order, and pattern. Part of that order of worship includes reading Sacred Scripture, and often preaching (in the form of a homily or sermon) that ties those readings into a message to help benefit, encourage, and guide the Faithful. To that end, the question throughout Christian history was, "Which books are to be read?" That is, which books should be read because they are, as Paul says in 2 Timothy 3:16, "useful for teaching, rebuking, correcting and training in righteousness,"
Which books are to be accepted as the Christ-bearing, divinely inspired works which should be read in the churches, that the Faithful are built up, trained in righteousness, where they are taught in the right way of Christ and His Church, rebuked of their sin, corrected in matters of faith and morals, etc.
As noted, that process of asking "which books are to be read?" was a long one, and is still an issue which divides Christians today--as Catholics say one thing, Orthodox another, and Protestants (generally) still another.
So this Bible, which we have received through the generations of Christians who came before us, is a volumous body of work which while supreme in its authority (I speak here as a Lutheran who adheres to Sola Scriptura), does not exist itself alone, as though in a vacuum; but which has been read, believed, confessed, and received within the specific and particular circumstances and context of an actively-lived Christian faith and community practicing and believing that faith together. The Bible is, therefore, a Church document, a distinctively Christian work with a distinctively Christian purpose: To guide us in the right way of faith in Jesus Christ, by bearing for us Jesus Christ, His life, His death, His resurrection, what He has taught, what He has given. In the form of both commandment, what God tells us to do and how to live; and in the form of promises, what God says He has done, is doing, and will do for us.
That is why "Bible-onlyism" really doesn't work. And why one can't take this minimalistic approach that you are taking. It treats the Bible as something foreign to Christianity, rather than situated right in the middle of Christianity.
There is a living and dynamic relationship between the believing people of God, the Church, and the received record and word of the Holy Scriptures, the Bible.
There's no good reason to take a "minimalistic approach". Consider the numerous heretical groups which claim to do something similar, claiming they only use and believe the Bible. Like the Jehovah's Witnesses, or the Christadelphians, and so forth. They are dismissing the history, the living context of Christianity in history, and trying to take part of that living witness, the Bible, and then build a brand new religion. But what they are doing will always be missing pieces, because the Bible on its own can't make Christianity. Christianity is made by Christ, and the living community of His people, in which the Scriptures are received, believed, and confessed as the holy and received word of God.
This is why Sola Scriptura is not Bible-onlyism. The way in which Scripture is alone in Sola Scriptura is in the way that Scripture alone is infallible, Scripture alone is unfailing, Scripture alone never errors nor fails to bear Christ to us. If the Scriptures are being taught properly, if they are understood rightly, if they are confessed faithfully, then the Church rests securely in this precious word, because it is the very word of God. But if the Bible is used wrongly, if the Bible is abused, or if the Faithful are deprived of its life-giving word, then the Church suffers, or even worse, we concoct a myriad of heresies which lead people away from Christ.
-CryptoLutheran