Deep kitchen cabinets look useful when they are empty. There is plenty of room, the shelf feels generous, and it seems like you should be able to store almost anything inside.
Then you start using them.
Cans collect in the front. Pasta gets pushed behind them. An extra jar disappears somewhere in the back. A few grocery trips later, you know the cabinet holds a lot—but you are not completely sure what is still back there.
The problem usually is not a lack of storage.
The real problem is that too much of the storage is hard to see and reach.
Quick answer:
A deep cabinet works better when you organize it around access rather than trying to fill every inch.
Keep frequently used items toward the front, use long bins or clear zones for grouped items, and consider a pull-out organizer only when you regularly need access to the full cabinet depth.