Before I delve into the answer here. There is something of far more importance that must be settled. You mentioned the word "supposedly infalliable," as if you are doubting God. Hopefully, the scriptures below will give you a better understanding and in turn, a greater trust in God's infalliable Word the Bible.
Titus 1:2: "Upon the basis of a hope of the everlasting life which God, who cannot lie, promised before times long lasting." God cannot lie. Simply put.
Hebrews 6:18: "It is impossible for God to lie."
2Timothy 3:16, 27: "All Scripture is inspired of God and beneficial for teaching, for reproving, for setting things straight, for disciplining in righteousness, that the man of God may be fully competent, completely equipped for every good work." Notice that these verses did not say "Some" scriptures is inspired. It says all.
Remember, we do not know every scripture in the Bible. Not all of them have been revealed to us. Only certain people can have that sort of information revealed to them by having Jehovah's holy spirit, or his active force.
Also, it is worth mentioning that Jehovah does not view time as we do. Why?
Isaiah 55:8: "For the thoughts of YOU people are not my thoughts, nor are my ways YOUR ways, is the utterance of Jehovah. For as the heavens are higher than the earth, so my ways are higher than YOUR ways, and my thoughts than YOUR thoughts."
How does Jehovah God view time?
2 Peter 3:8: "However, let this one fact not be escaping YOUR notice, beloved ones, that one day is with Jehovah as a thousand years and a thousand years as one day."
To the One who lives forever, a thousand years are as one day. He is not restrained or pressured by time, like we are, because our time is limited. We think only of a day in terms of 24 hours constituting as a single day. Jehovah thinks far grander than that.
Really, what we see happening today is merely the long-term result of what Adam and Eve did. Man still has not returned to the rulership of the only One who can guarantee his happiness and bless him with what are known as “human rights.” Until he does, he will never enjoy those rights.
No one has lived a thousand years, according to Jehovah. Here is a better picture of how Jehovah would view our time.
1,000 Years = 1 Day = 24 Hours
500 Years = 1/2 Day = 12 Hours
250 Years = 1/4 Day = 6 Hours
125 Years = 1/8 Day = 3 Hours
62 1/2 Years = 1/16 Day = 1 1/2 Hours
31 1/4 Years = 1/32 Day = 3/4 Hour (45 min.)
15 5/8 Years = 1/64 Day = 37 1/2 Minutes
How old was Adam and Eve in comparison to Jehovah's Day? How old are we according to Jehovah's Day? Did Adam and Eve live for a thousand years? No. How is that proven in God's infalliable Word the Bible?
Genesis 5:5: "So all the days of Adam that he lived amounted to nine hundred and thirty years and he died."
As close as 930 years of age is to 1,000; he did not live a full day, according to Jehovah God. In essense, Adam and Eve died in that "day." That same day they sinned, they died, although not instantly. The point is that they did not live for 1,000 years, which would constitute as one day to Jehovah. We do not even come even within shouting distance when we compare Adam's years on earth compared to us as humans, who may live 70, 80, 90, 100, if that?
How magnificent is Jehovah? Is God's Word "supposedly infalliable?" No, God's Word is infalliable! Why?
Deuteronomy 32:4: "The Rock, perfect is his activity,
For all his ways are justice. A God of faithfulness, with whom there is no injustice; Righteous and upright is he."
Who of us can match that?
Either we follow our own course and suffer the consequences that Adam and Eve did or follow the laws, principles, standards, reminders, commandments and orders as set forth in the scriptures? The majority of the people do not follow the latter because their actions show its true colors.