Thank you for your biblical question, “Is it possible that Joshua would have unofficially begun the time of the judges in ancient Israel upon entering the promised land?”
It is possible that the time of the judges could have begun at the end of Joshua rule, but unlikely at the beginning of the Israelites entering the Promised Land.
Here are some thoughts for one’s consideration:
A. The Book of Joshua does not mention the rise or need of judges upon entering the Promised Land.
B. The deterrence of disobedience by the Israelites entering the Promised Land when they saw their parents died in the Wilderness.
C. The defeat of the Canaanites by the Israelites in entering the Promise Land would most likely kept the Israelites adhering to the words of Moses and Joshua.
D. The deception of Achan and the Gibeonites is the only two recorded of disobedience by the Israelites.
E. The lack of recorded idolatry by the Israelites as they entered and conquered the Promised Land reflects the faithfulness of Israel.
F. The centrality of the Tabernacle and the leadership of Joshua within the Israelites’ encampment kept the Israelites faithful.
In my view as the Israelites began to take possession of the Promised Land that the Israelites began to wander from their LORD God. The Israelites were on their own living in various parts of the land that still needed to be conquer. In order words, Joshua wasn’t leading them into the smaller battles. In addition, there is the passing of the second generation with the rising of a third generation who may not have experience or known about Moses or had seen the wonderful works of God. Finally, the second and third generation wanted to settle down and establish their homes. They may have been tired of war and wanted peace, nearly at all cost. Thus it is more likely at the end of Joshua’s life that the Israelites began to compromise the Law that was given to them by Moses. Joshua’s challenge at the end of his life to the Israelites was short lived as God didn’t raise up a central leader after Joshua’s death. Each of the tribes were living apart from a the Tabernacle and from a central leader at the end of Joshua’s leadership. Idolatry began to creep into the lives of the Israelites.
SUMMARY: As long as the Israelites were encamped around the Tabernacle and seeing Joshua, the Israelites were faithful to God. It is only when they went to possess their allotted portion and the death of Joshua that the Israelites began to wander from God.
For further discussion: