It could possibly dilute the brand if the three different iPhones all looked very different to each other. But what if they all looked very similar to each other in shape and design? I think the brand would be stronger than ever, and more importantly it would be more diverse and appeal to even more people
So, you're saying Apple should make the iPhone a commodity?
Apple didn't accumulate $95+ billion in cash reserves by making poor business decisions. Their 17% market share captures approx 75% of the cellphone market's profit.
Apple is marketing and selling a brand. You don't want to dilute the brand.
This from the spouse of a CMO for a tech company.