>>1068628>Using the tops as the primary position
That would be the hoods, you know, the position that you can still brake and shift from. The tops are only there as a temporary position to take some weight off the hands and straighten the back.
Now, while the hoods and flat bars should result in fairly similar body positioning if you can't bend down far enough to use the drops (perhaps it causes him pain or he simply can't bend that far at all) then it doesn't make sense to have them.>>1068626
It does to some extent, but yes geometry, stem choice, and fit are also factors. And as above it's not so much that drop bars would force a more bent over position, it's that they would allow that position.