Will a ball python survive on a small rat every week? Yes.
Will a ball python survive on a medium rat every other week? Yes.
Will a ball python survive on a large rat once a month? Yes. (I have one that was fed like that with its previous owner- she's 8-9 y/o now)

The "controversy" your talking about involves a theory that feeding ball pythons multiple smaller items causes them to be overall more consistent feeders, a desireable trait especially if you are considering breeding them.

While your arguement that when in the wild, ball pythons can't be picky as far as what size prey to eat, does have some merit to it, there's one thing about that premise that kind of knocks it all down: this isn't the wild. When talking about ball pythons in captivity, its really a whole new ball game (no pun intended!).

I'm a believer that consistant husbandry for ball pythons in captivity lowers stress and allows them to thrive in a relatively unnatural setting. Consistant temperatures, maintenance routines, and consistant feeding. If you choose to feed your ball pythons multiple smaller items, great. If you decide to feed them something larger every 10-14 days, thats ok too. Some have observed that the "multiple smaller items" makes for more consistant feeders, since I switched to that routine I've noticed more growth and consistency in feeding, and at the same time you aren't hurting them by feeding larger stuff at a longer interval.