I agree with you, but it got me wondering. What about before we had the official Bible?
Before we had the "official Bible" (or more precisely the Bible as we know it from a non-Catholic perspective), God gave Israel the Old Testament (the Tanakh) which was completed about 400 years before Christ. When the Lord Jesus Christ walked on this earth, that Hebrew Bible was God's revelation to men, while He Himself was the living Word of God revealing the Father to mankind. By about 90 AD, the complete Bible was available in the form of manuscripts. By the 14th century there were printed texts of the Hebrew and Greek testaments, and also translations in many languages. So the Bible has been around for about 3,500 years (partially or completely).
Or people who still don't have access to one?
Today the Bible can be accessed in almost every language on the internet. So this is a non-issue.
God still speaks to them. All of creation speaks of His name. If God only revealed Himself through the text, then only those with access to the text could hear Him.
Yes God does reveal Himself through His creation, but no one will learn of His salvation through creation. Therefore Christ has commanded His Church to preach the Gospel to every creature, and the Gospel is also called "the Word of God". Where is this Word found? In the Holy Bible. So creation is obviously insufficient.
Since God has reached people in other ways, would that mean that we can also gain understanding of Him outside the Bible?
God can speak directly to men, and Christ does so even to this day. That is not the issue. Because God has given man His written Word, and because it is now available in almost every language, and because it reveals (a) the nature and character of God, (b) the nature and redemptive work of Christ, (c) God's eternal plan for redeemed and restored Israel, and (d) God's eternal plan for the Church, we turn to the Bible to know the heart and mind of God and of Christ.
As to your Bible study, since Scripture interprets Scripture, Christians must rely on Scripture to explain itself (while ensuring that only a reliable translation is being used). At the same time, there are legitimate Bible study tools such as concordances and lexicons, which can assist in studying Scripture, and which should be use. But the Teacher is always God the Holy Spirit, and if we resist God's truth when it is revealed, we will not be given more light. God's Word is meant to change hearts and lives, therefore its study is not a mere academic exercise.
Commentaries should only be consulted by those who are already solidly grounded in the Word, since they do present theological biases, many of which are erroneous. The commentaries which are sound can be helpful, but God requires that every believer personally study His Word.
Prove all things, hold fast that which is good (1 Thess 5:21).