A simple read through of the OT shows the title of this article is completely wrong.
Yes, they were told to wipe out the Canaanites before they entered the promised land. But almost from the beginning, they failed to do that! They were tricked by the Gibeonites, who acted deceptively, and pretended they were from a far away land, and had Joshua promise he would not kill them in Josh. 9. Joshua had a successful campaign north, including burning Hazor to the ground. (Josh 11:1-15) The Bible says he also conquered the Negev, the land of Goshen, the foothills, the Arabah, the hill country of Israel, up to the valley of Lebanon. (Josh 11:16-23)
The Israelites also took the land east of the Jordan (Josh 12:1-6), territory west of the Jordan, (Josh 12:7-24) The problems started when Joshua started to get old and their were unconquered lands left. He lists the land that remains in Joshua 13:1-13.
"Yet the people of Israel did not drive out the Geshurites or the Maacathites, but Geshur and Maacath dwell in the midst of Israel to this day." Josh. 13:13
In fact, the first sentence of the books of Judges states the fact that the Canaanites and other people had not been killed or driven out of the land.
"After the death of Joshua, the people of Israel inquired of the Lord, “Who shall go up first for us against the Canaanites, to fight against them?" Judges 1:1
The areas never conquered included Philistia, Phoenicia, Aram, Geshur, Maacah and the Valley of Jezreel. Judges 1 contains more on this.
Articles like this should get their basic Bible facts down. It is important to know the Israelites did not drive the Canaanites and other people's out, because this is how they got seduced by other gods, which ended the nation of Israel, as God used the Assyrians in 722 BC to carry Israel into permanent captivity, and the Babylonians to carry away Judah in 586 BC, into captivity, because of idolatry.
I highly recommend people read the OT narratives if they want to know more. They certainly are an exciting an interesting read!