Apple did respond! For the antenna issue they held a press conference and blamed the issue on how the phone was gripped. They offered rubber bumpers as a solution. For the phone's power management limitations, they tried to conceal its existence with software rather than recommend battery replacements (Apple doesn't want people to maintain their devices. They want them to buy more). Ultimately, the weasels had to come clean and make battery replacements convenient. As for the recent iMacs and MacBooks they had to create extended warranty programs to manage not only the existing wave of reported failures, but also the potential wave that is to come.
Apple's problem is the sheer number of devices it sells. When a design decision creates an issue, it's potentially expensive for Apple to renefy. Therefore, Apple's initial response is to be secret about its existence and cause. As reports increase, Apple denies it is an actual issue, insisting the causes are varied and due to User behaviors. When the lawsuits are filed, Apple suddenly discovers that the issues are due to a precise design or manufacturing defect, and they will accommodate Users who haven't already paid for repairs or parted with their device.
You're myopic to assume that the collective volume of sold products is evidence of their reliability. Apple has an unusual number of service portals. If the demand for repairs wasn't there, I doubt Apple would feel they were necessary.