Firstly, reach and drop are not the same thing, as the OP indicates.
Drop: I like enough drop so that when my forearms are horizontal, my thighs clear my chest by some small amount. IOW as aero as I can get and still breathe comfortably.. .
Reach: I like plenty of reach. I think it unloads my hands and is more comfortable on rough roads. With horizontal forearms on the hoods, my knees are very close to my elbows. This lets me flatten my back while still using my upper arms as struts.

I've always had about the same position, hasn't changed with age. I do all sorts of stuff to keep it that way. But I think some people have various back disorders which prevent them from bending in the lumbar area. And many more people simply aren't in good enough shape to be comfortable like that. It takes constant attention. One of the very best exercises is simply walking for a few miles at as fast a pace as one can manage. Super for the lower back. A low back makes it so much easier to be fast on the flats and false flats. Torso weight is in the right spot and the swept rectangle is smaller.