I think the problem is that the base models Apple offers and unbalanced on purpose, they are ridiculously powerful in terms of CPU/GPU but hobbled by the skimpy amount of RAM/storage they come bundled with. Apple simply decided that it isn't profitable enough to offer "balanced" base models, so they do this.
I would gladly pay a little more to have a balanced base-model device which would keep Apple's margin per unit the same or even a little higher, but they don't want to offer this. Their strategy is to increase profits over time (and not only per unit sold) by guaranteeing that either 1 - the buyers of the base models will feel the need to upgrade sooner rather than later not because the CPU/GPU are insufficient, but because they can't upgrade RAM/internal storage, or 2 - make "upgraders" pay much higher margins to Apple on the spot through the extortionate prices of RAM/SSD they charge on BTO options.
This may be all legit, companies maximize profits, blah blah blah, but it certainly feels scammy if you understand it.