Revenue =/= profits. Amazon is a middleman and are only successful at generating revenue growth because they don't make profits.
Plus most of their sales were B2B where brand loyalty means little for commodity products, esp. given the high tie-in strategy.
Apple: We sell an experience of software and hardware. Google: We sell ads, based on data we gather from our users. Amazon: We sell commodities\services as close as possible to the marginal utility, so we're very competitive.
Altough each of these tech giants are competing, each has quite a different strategy.
As for the Fire phone, I think that Amazon realized that they could deliver an excellent shopping experience from the mobile phone. This would enable massive future growth: Think about going home in the train and buying groceries instead of driving to your nearest Wallmart.