Denying potential customers a device and delaying giving it to them for months increases the chances those customers will go purchase something else. Or won't get anything and will just wait for the 'next thing'.
No, there's no salacious conspiracy here. It's simply the consequence of trying to manufacture cutting edge technology with new factories (to try to produce the mass volumes of that new tech) for millions upon millions upon millions of customers. There's always issues with new tech and the production thereof. There always has been and there always will be. Companies like Apple absolutely want to get as many of these devices into the hands of customers as quickly as possible.
I disagree. Those who want an iPhone won't "purchase something else". They will wait. They will whine. They will complain about the availability. But they will wait. Apple knows that. Apple also knows that there will be an incredible demand, yet they manage to have some kind of production/yield problem every year, with every device. What I find most interesting, is that they are playing "catch up" with much of the technology. They do improve it, but they are still adding features and components that Android has offered for years (OLED screens, for example)...
Apple could solve the issue each year ahead of launch, but then they would lose the spotlight in the media sooner... all of the buzz about how hard it will be/is to get the latest and greatest is something Tim Cook relishes. To solve that would be losing that buzz far to soon for his liking.