I get what your are saying, to a point. But just throwing numbers out there and comparing amp hours vs cost and the flexibility to service your own gear is not tantamount to saying you are building superior systems to what some of these companies are doing, and I don't mean eg4 and big battery. All you are really saying is you can build a bigger system cheaper. But until you've got the empirical longitudinal testing and you've actually accrued enough legitimate data resulting from head to head shootout trials, that's really all you are saying. Of course, your not likely to do all that, and neither are most other people, certainly myself included. Sure, you might get ten years from your bank and have to swap 2 or 3 cells and a new bms in that time, and my commercially made batteries could perform flawlessly under identical conditions without needing anything, and you still would have spent less money (a lot less), but I would still say mine was the superior battery, just at a greater expense. I guess it comes down to individual definitions. I suppose the truth of the matter is that ten years from now, it's fairly likely there will be far better, more flexible, cheaper battery options anyway, and longevity concerns of what we are using, buying, or building today will be a non issue, in retrospect.
