Consumers generally have a responsibility, but practically speaking a customer can’t know every fact about a product before buying, which is why there are laws to protect consumers from sellers exploiting (wittingly or unwittingly) that limitation. The questions to argue then is of course what facts about a product should the company be forced to divulge, but also to what degree is the company obligated to make each fact obvious? Because there is also a limitation to what a customer can notice at a practical level. This is precisely why the surgeon general’s warning must be on cigarette packaging and at least a certain size.
In this case, Apple does have that information available to customers, but I’d argue that Apple is not doing enough to make it obvious. The reason being, phones and electronic products in general have always included chargers. Though generally not a legal obligation (nor do I think it should be in this case for Apple), it has become a common understanding.
Say there is a store that has a window plastered with signs about their rules and policies, and there are regular customers who come in day after day for many years and the rules always stay the same. Then one day the store decides to put up one small sign among the myriad of signs that says by entering the store you give up your hat (silly example). In order for the regular customer to notice this sign, they must read all the signs every day before entering. If every store did this, customers would be expected to spend a large portion of their time every day reading signs, and little to no time actually buying things. Everyone loses in this case.
So for practical reasons, the store would temporarily put out a prominent sign notifying customers of the new rule, until after a time it is relegated to join the other signs on the window. So too a company should be obligated to take a more active approach to explicitly tell the customers of new important changes.
Right now Apple’s site does show “what’s included” at the bottom of the purchase page a little ways BELOW the “continue purchase” button (so it can easily be missed) and of course simply does not picture the charger. And they explicitly say below that that the charger is sold separately, but in fine print. Same with on the box. But these are either passive omissions or too inconspicuous. I argue Apple needs to actively and explicitly inform customers that the charger is not included in a prominent manner that is designed to get customers’ attention—on the purchase page, in physical stores, and perhaps on the packaging itself (though maybe a sticker that can be removed by the customer if desired).