The Torah does not end on a high note, but on a solemn one. The final dual reading — הַאֲזִינוּ Ha’azinu (“listen,” Deuteronomy 32) and וְזֹאת הַבְּרָכָה Vezot Haberachah (“and this is the blessing,” Deuteronomy 33–34) — is written so that when the descendants of Israel eventually hit rock bottom, they would see the way back home.
This restoration only is possible by the perfect Atonement offering — the Mashiakh (Christ). This is why we read through the entire Torah over the course of the year and put into practice those things that apply to us.