From my perspective, I've never seen any edition of D&D that was a complete solution (no added/replaced rules necessary) out of the box. Its why so many groups have house rules. The idea that I can buy an edition of D&D and everything works within itself to accomplish all the variety necessary to depict a game that works best for my particular group - doesn't exist. I always change, add things, replace options in every edition of D&D, and now Pathfinder.
I am puzzled that you (Danny Alcatraz) would believe that any out of the box RPG is going to be complete in of itself, and not require some level of tweaking to work best for you or your gaming group. Perhaps its true for you, but I've never found it so, not in 35+ years of playing the game.
As an aside, I've never used a Mac, all my computer experience is using PCs, thus I don't buy computer equipment as one brand to handle everything I need. Being modular is the way I buy everything. So the video card, pointing device, operating system, software applications, monitor, and every other component, I buy based on what I believe is best for me for each individual component. Because I also want the best price for these individual components, I often purchase them separately from different stores and distributors, and build the whole myself once I have all the parts.
When I create maps, I mostly rely on one software, but often my maps are generated using 3D modeling, 3D rendering, texture mapping, hand-drawn elements that are digitally scanned, using photo resources, and much of this work is done by different applications. So even in creating maps, I generally don't use one software only to do the job, rather 3 or more different applications created by different companies are used to create various aspects to my maps.
So the same philosophy in building component based RPGs is the same philosophy I use to build me a computer, or create a map. One solution doesn't exist to accomplish any the tasks I need for any activity that I participate in. I use what is best for each individual step, and each may be completely different entities.
I will clarify by saying those things that don't matter much to me, I don't spend as much thought to 'componentize' and might buy "as is" to serve me. My car, for example, is a means of transportation for me, and I otherwise don't give much thought to it, so I generally buy a vehicle and not try to improve it with various add-ons, like everything else I do put the effort in. Things that matter, I do buy piece-meal and build to suit my tastes. So my 'philosophy' doesn't apply to everything in my life, only those things that really matter to me.
I am puzzled that you'd find the way I do things as puzzling?