Right, and this is because of consistent components and internal APIs in conjunction with enforced deprecation. This was the goal of gnuStep[1] and (more direct

Right, and this is because of consistent components and internal APIs in conjunction with enforced deprecation. This was the goal of gnuStep[1] and (more directly) etoile[2], but those projects appear dead these days. 1 - http://www.gnustep.org/ 2 - http://etoileos.com/