Yes it is. In fact, there has been plenty of debate. The fact of the matter is the apostolic fathers themselves wrote down the gospel for the purpose of handing it down faithfully. Luke himself, in his prologue says as much:
“Inasmuch as many have understaken to compile an account of the things accomplished among us, just as they were handed down to us by those who from the beginning were eyewitnesses and servants of the word, it seemed fitting for me as well, having investigated everything carefully from the beginning, to write it out for you in consecutive order, most excellent Theophilus; so that you may know the exact truth about the things you have been taught.”
In his rebuke against the Judaizers, Paul states: “I am amazed that you are so quickly deserting Him who called you by the grace of Christ, for a different gospel; which is really not another; only there are some who are disturbing you and want to distort the gospel of Christ. But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed!”
The apostles themselves saw fit to write the Gospel accounts and epistles to instruct or correct the Church, even while they were alive. They no longer live, but their gospel lives on in their writings inspired by the Holy Spirit. Which is why since the sub-apostolic age forward, the Early Fathers have always appealed to the scriptures for the same reason, and why Paul himself recommends to Timothy to remain grounded in them.
Sola Scriptura is not attempting to address how the gospel was transmitted immediately after Pentecost. It is addressing what has been given to the Church today by the apostles to assure that our proclamation of the Word is in accord with what the apostles actually taught. And what we have today is their writings inspired by the Holy Spirit for that purpose. The scriptures are the means by which we norm our doctrine and proclamation of the Word.