In the Torah reading דברים Devarim (“words,” Deut. 1:1–3:22), Moses started giving a more complete record of what happened during the entire 38 years in the wilderness.
The Israelites didn’t have the same degree of bravery as their cousins (Edom, Ammon and Moab). They didn’t follow God’s direct instructions and suffered as a consequence. Their leaders became rotten; they ignored Torah, and the people suffered as a consequence.
This is why God hits the reset button from time to time (e.g., the Flood, first-born of Egypt, Day of the LORD), and sets aside a remnant to carry His truth into the world. A remnant is more teachable than a mob.