I'm thinking about the conquest of Jericho (Joshua 6). The people marched around Jericho a bunch of times, then an earthquake shatters the wall and the city is conquered. If this were a video game, you'd say "Great. I love this level! I'll use the earthquake in every battle from now on."
The people are overconfident when they march against Ai in chapter 7. One might think that after Achan's sin is exposed and he confesses and is judged, the people can go back to marching around the enemy until the earthquake pulverises them. But that isn't what God does -- Ai is defeated by a battle plan that doesn't involve earthquakes or any other miracle. And the rest of the battles don't involve earthquakes. There is one more miracle in Joshua, the day the sun stands still, but the rest of the battles all involve hard combat without miracles. I think God wants us to understand how He is powerful enough to enable a miraculous victory at any moment, but he also wants us to understand he often chooses not to display that power.