Why would anyone solo Ragnarok Raid battles? It's a waste of time. It's the sort of thing people do just to show they can. All that counts is being able to shave off enough HP to get the MVP. Doesn't take a perfect team with elemental advantage to do that. I've joined 2 Wind Disaster Ragnaroks with half-baked Water teams I slapped together (one where I used Mordred and mostly spammed debuffs that mostly missed) and got the MVP each time. And it's not like BP is a super-limited resource.

And in the end, when players are using 2 grids of equal strength (let's say both are maxed grids) the ones using fire against this current wind ragna, or w/e has ele adv over what they face will always out damage the ones using off-element.
Yes, if you put in 6x the effort and resources over the course of 1-2 years you'll do marginally more damage than those who put in 1x the effort and resources. Is that the point you're trying to make?

You do it because it lets you kill all the matching elements faster and easier.
You only need to farm for every element if your strategy relies on having teams for 6 elements that are endgame-ready. Take Guild Orders, for example. Let's assume your goal is to farm orihalcum for weapon final limit breaks. Sure, maybe you can farm more orihalcum per event. But because you run 6 teams, you NEED more orihalcum than someone who runs only 1-2. All you did was increase the speed of your treadmill. Same applies to Tower events. Union event rankings rely more on time commitment than anything else, and rewards follow the same pattern.

In any case, you ignored the specific questions I asked in favor of a sort of long diatribe. While it was interesting, my questions remain unanswered. I'm not even asking for justification at this point. Just answer the questions. We can work from there.

The difference between you and me is that I try to write for a general audience. The optimal solution for one player may be sub-optimal for another. I don't have the luxury of assuming that my audience exactly shares my conception of how much time and money one should sink into this game. Even when I don't agree with a certain perspective, I have to understand it to be able to provide a set of alternatives given different sets of premises--which is why we're having this discussion.