hashem continues promising His support if the Jews continue serving Hashem and not turning away to other gods. Hashem says in 23:29, "I will not chase [the enemy nations] out [of Israel] in one year, lest the land become desolate and the wild animals will overtake you."
In 23:33 He implores them to not make treaties with the various enemy nations and not let them continue living in Israel. He says, "Do not let them live in your land, lest they will lead you astray..."
First Hashem says He will only get rid of them slowly so as not to put you in physical danger but then he warns you against letting them continue living in Israel.
Look at the great risk Hashem was taking in order to protect the Jewish people. There was a basic inherent risk in letting the nations stay in Israel with the Jews. It was clear and obvious that they would cause the Jews to sin. But Hashem was willing to ignore that, at least in the short term, just so that the Jews would not be in danger physically from animals.