defstructs and packages

Why CL includes two non-orthogonal concepts for code organization? Why to define an IMAGE package I have to separately declare (defstruct image-state ...)?

Can we replace defstructs with packages in future Lisps?

For example, following simple functions could be used to transparently attach info (like package or source file) to any heap-object

(defparameter *meta-db* (make-hash-table :test 'eq))

(defun meta-set (info object)
  (setf (gethash object *meta-db*) info))

(defun meta-get (object)
  (gethash object *meta-db*))