Since we really don't want to limit ourselves with indie companies, let's focus on AAA.
That is part of the disconnect. You are discussing AAA, but the discussions you are critiquing are virtually all hobbyists.
Obviously with a AAA company and a 15-200+ full-time team, like WoW, LoL, Sim City etc you have not only the budget but also the need for some pure designers, ideas guys etc. Keeping track of game balance and coordination at that level can be more than 1 full time job.
But that isn't what is being disussed at least with any of these conversations I've seen here. They are all being posed by people who have no experience in the industry besides at most a couple years on the hobbyist/indie side (and frequently not even that). The context is hobbyist, unpaid teams of people (frequently trying to produce something just like WoW only 10x better
).
In this context, the problem is almost always that people dream up ideas that are unrealistic compared to the amount of coders and artists involved in the team. It is good to dream and have passion, but part of taking it to the next level is coming up with a realistic plan that has some chance of success. To that end, the majority of these people (who don't have coding or artistic skills)'s best course for success involves: learning coding, learning art, recruiting coders, recruiting artists, or joining an existing team that already has assembled some coders and artists.
Even in AAA companies, the vast majority of people are doing coding or art. Your chart and reasoning attempts to apply the same weight for a Finance person as for a coder as says "see, people with coding or artistic skills are in the minority!", but if you actually factor in ratios, you get to something closer 80%+ of the staff are coders, artists, and musicians.