Isn't the problem with that analogy that there are things like NURBS which are pretty directly analogous to vectors (and isn't a surface a boundary?)
Edit: Along with the fact that blender has a lot of non destructive workflow steps (that usually get baked out into the "bitmap", to further your analogy)
It's not a perfect analogy, and Blender does have some parts which resemble the sort of data structures you'd use in a CAD modeler.
I think with enough plugins and customizations, you _could_ twist blender into something that resembles a CAD modeler, but it's really an uphill fight compared to selecting tools which were designed with that goal in mind from the start.
Edit: Along with the fact that blender has a lot of non destructive workflow steps (that usually get baked out into the "bitmap", to further your analogy)