I've come to realize that God doesn't just want to bless you make it to the mountain; He wants to keep you there. Furthermore, God needs to make sure you know how to function there. In order for that to happen, He has to deposit certain fruits into your spirit that can only be done during your valley. Humility and patience are not instant but they have lasting effects. I truly believe this is what God meant in James 1:2-12.
The reason why you count it pure joy in struggle is because you know that struggle purges the spirit of arrogance and creates the opportunity for faith activation. The depth of your valley is a sign of the height of your mountain. See Romans 8:18 and 2 Corinthians 4:8-18. The deeper you are the more blessed you will be. And in that is where you will find your joy. Count on that!!!