I haven't seent he first post, sorry..
But, tapers are selected for different reasons and designs. Limb lams might possibly even taper from thin near the handle to thick at the ends, called a reverse taper, if the design calls for it.
Most designs must either taper side to side or back to front so they will bend correctly. Since the area near the handle has the length of the limb exerting more leverage on it, it is usually the most massive there, and stiffest. A taper that is fatter at the handle and thinner at the tips accomplishes this.