For years, Apple, especially in the era of Steve Jobs, was known for making quality products that would last for years longer than cheaper alternatives. With the problems reported with the new iPhone, this aura of dominance will start to lose sway with Apple customers as they realize the quality of products has suffered under the post-Jobs regime; as a result, their loyalty will weaken and they will be more willing to seek out cheaper alternatives.
Despite problems reported with the iPhone 6, consumer loyalty to Apple will continue to be strong due to a number of factors that all revolve around positive reputation. Apple has a reputation of providing an innovative product that has cool designs, applications, and overall favorable usage. Apple products have differentiated themselves as a quality product with prestige that many people see as a premium product that they must have.
The iPhone 6 has already had reported problems. But, problems were also reported about iPhone 5 and iPhone 4 before that. It did not affect sales because iPhone users generally have a high level of loyatly to Apple products. A few problems would not be enough to convince them to purchase a different phone.
Apple is synonymous with quality technology. Most, if not every phone, has had some issues upon introduction to the market. With a little time, the problems will be fixed and Apple will leave this saga behind. It's highly unlikely that people will jump ship and abandon Apple because of what's been going on with the iPhone 6. If problems continue to occur and they can't address them, then maybe Apple has a problem on their hands. But for now, they don't.