You are comparing a company that makes a phone where one button MAY encounter issues with a company where a manufacturing fault can cause loss of life. Also, I am fairly certain that, at least in countries in Europe and North America, car manufacturers are legally obliged to replace/repair recalled vehicles. No such legal requirement exists for Apple. Some people may not like it, but it is what it is.
First of all, you said that "...Apple should fix the problem...". I agree with a caveat: should, not must. Big difference. Second of all, you say "...it is their obligation to fix the potential problem...". I do not agree: Apple are not obliged to do anything that is not mandated by consumer protection legislation in markets where Apple operates. If they go above and beyond what they have to, as they often do, kudos to them. The fact that came out with this 1.5 years after iPhone launched should be commended. Clearly not all iPhone 5 manufactured up to March last year were affected, not in the least because this is a combination of sporadic manufacturing defect with wear and tear that occurs naturally. As with any manufacturing process, there are bound to be imperfections at the beginning and processes are refined and improved with time. Using your analogy, this means that initial batches of any product are bound to be less than 100% than subsequent ones. Sorry, nice try, but you are not going to convince me, much less Apple, that what you say is sound. Would be nice but, alas, c'est la vie.