No, I don't think the people died because Joshua didn't ask God. God was showing Israel the importance of obedience. It was serious enough that Achan, his whole family, and even their animals were stoned to death.

You really can't apply these verses from Joshua to mean that we can have victory in the Christian life this way. I have no physical enemies to defeat. The New Testament doesn't talk much about victory:

(1 Corinthians 15:55-57 NIV) "Where, O death, is your victory? Where, O death, is your sting?" {56} The sting of death is sin, and the power of sin is the law. {57} But thanks be to God! He gives us the victory through our Lord Jesus Christ.