Actually, they were received and accepted as Divinely-inspired scripture long before. From The Formation of the New Testament Canon:
The Muratorian Canon: This document gives a list of the canonical books with some comments. It was discovered in 1740 by the antiquarian L.A. Muratori. It is believed to have been written in Rome towards the end of the second century. It is the earliest extant document in which the canon is treated in a formal fashion. It states what documents are to be regarded as canonical and which are to be rejected. 22 It is unfortunately a fragment. The meaning is also obscure at points. It lists all the books of our New Testament except Hebrews, James and 2 Peter. There is also a question as to whether 1 Peter is mentioned. It includes one book, the Apocalypse of Peter (2 Peter?), which was subsequently rejected. The author of the Muratorian Canon himself has his hesitations about the book, for he notes that some do not accept it. The main value of the Muratorian Canon is that it indicates the books which were recognized as canonical in the Roman church towards the end of the second century. In this document we are already very close to our New Testament.
Irenaeus (ca.130-200), whose writings are contemporary with the Muratorian list, presents the same picture. His evidence is significant in that he was a rather ecumenical figure in his day. He spent his earlier life in Asia Minor and his later life in Gaul. He was also in close touch with Rome. He does not seem to have had Hebrews in his canon, and there is some uncertainty as to whether he accepted the general epistles (except 1 Peter, 1 and 2 John). He refers to the Shepherd of Hermas as "scripture" but does not include it in the list of apostolic writings.
Tertullian (ca.160-220) is our authority for Africa. He appears to have had 22 books in his canon — the four Gospels, Acts, the thirteen epistles of Paul, 1 Peter, 1 John, Jude and Revelation. He did not treat Hebrews as canonical.
Origen (ca.185-254) in the East has a good deal to say about the canon. According to F.F. Bruce, "He acknowledged the four canonical Gospels, the Acts of the Apostles, the Pauline epistles and Hebrews, 1 Peter, 1 John and Revelation as 'undisputed' books." 24 Origen does acknowledge, however, that Hebrews, 2 Peter, 2 and 3 John, James and Jude were rejected by some.
The formal creation of a "canon" or rule of faith came about as a result of various heretical movements that challenged the already accepted body of sacred writings passed on through the Apostles.
Sola Scriptura, while un-Biblical, was also impractical, at least until the advent of the printing press. No one could afford a complete Bible (handwritten on scrolls). Nor could a significant number even be manufactured to make the doctrine practical in any meaningful sense.
Since few books of any kind existed, most people were illiterate, for more than a millenium.
TODAY, 800 MILLION ADULTS ARE ILLITERATE.
How does Sola Scriptura work for them?
The same way as always, those who COULD read taught and handed down the teachings from God to those who couldn't. Did having a segment of the populace unable to read negate the holy Scriptures believed, obeyed and preserved prior to Jesus' coming to earth? That was the example the early Christians continued under the leading of the Holy Spirit. Being unable to read in NO way diminishes the FACT that the Holy Spirit inspired prophets to speak God's word and record it for posterity and the people of God commanded to obey it.
Far from Scripture opposing Sola Scriptura, we have multiple passages that confirm the authority of God's word. The "church" is and has always been the servant of God's revealed truth and is tasked with being the buttress and supporter of the truth. The early creeds, developed to dispute heretics, affirm the truths AS revealed in the Bible. Where else would they have come from? Jesus used Scripture to confirm His role, the truths He spoke and the truths He intended to be passed down through the church age. There really is no human authority that has preeminence over God's word and those who presume they do will answer to God for their error.
Like I said upstream, it was all pretty much decided much earlier. That explains why we have the books we have. The “books” we consider canon today were copied and passed around the early churches resulting in the vast number of manuscripts in existence today. They were recognized as authoritative. All Rome did was put their rubber stamp on what was already there and to this day Roman Catholics are spiking the football for acknowledging the obvious.