One thing I learned from looking at your photos: Before defoliation, many large leaves are shading out lower leaves and branches. Eventually those hidden ones will weaken, I would guess. By defoliating the tree is caused the tree to form a more evenly distributed new canopy. All branches are forming equally healthy leaf tips.

However, I will give you credit for good branch pruning probably also aided the tree to rehabilitate a more even distribution. It is keeping those lower branches just as vigorous as the top younger ones.