If that's the case, then how/why does Apply only charge $1/mo for their base iCloud plan?
Maybe they just want people to be used to getting a monthly invoice from them. Or to used to paying for cloud storage (and so willing to increase the limit if needed). But then the $1 tier is pretty generous so maybe they want you to store a load of data in their cloud so you’ll continue to buy their products.
That then allows for impulse purchases (movies, apps, etc), and validates that the user is not fake. One whale can pay for a lot of users.