Items in the droppers which created by the command block will not disappear but continue to reproduce itself

This issue keeps coming up. The problem is in your code

/setblock ~ ~ ~5 minecraft:dropper 0 replace {Items:[{id:35,Damage:0,Slot:0}]}

is not typed correctly. It needs to read:

/setblock ~ ~ ~5 minecraft:dropper 0 replace {Items:[{id:35,Damage:0,Count:1,Slot:0}]}

The Count is required. in this case when the wool is in the dispenser, activating the dispencer will make an entity apear in the world but not subtract the wool in the dispencer because of not knowing the count. Because you don't have the count the dispencer doesn't actually see anything chaning inside itself since no count means whats in there can't be reduced by 1 (i.e. 0-1 equals a -1 which can't happen so the dispenser assumes it remains the same). Using your code if you take the wool out of the dispenser and try and place it it will disapear as the quantity value will move with the item since you are manually moving it and not letting Minecraft calculate dropping into the world. You have to have a Count in the set block text string in order for it to understand whats going on.

NOTE: Not putting the count in there though can result in an unlimited ammo refil station by putting arrows in the dispenser. Since no count means the arrow in the dispencer never gets used and the created arrows the dispenser spawns are based on calculation and actually exist the dispencer will continue to make arrows from nothing.