Apple as of years ago was capturing over 90% of all the margin in smartphones (https://www.cnbc.com/2016/11/23/apple-captures-record-91-per...). I'd argue that represents a monopoly in paid smartphones. Our option as users is either buy a phone from Apple or accept what is essentially a free service from Google (you have to buy the hardware)... who are giving that away to solidify their search monopoly. This to me doesn't represent a thriving marketplace of user choice.
90% of global smartphone profits does not mean 90% of devices in the market. It's been demonstrated for years that iPhone users are much more likely to pay for apps. It's possible to be extremely profitable and not have a monopoly on the market because the iPhone isn't just an appliance but a Veblen good as well.
It does however mean Apple has significant market power. Almost by definition: in a very counterfactual perfectly competitive smartphone market, everyone sells at cost and there aren't any profits. Reducing it to monopoly vs. not-a-monopoly is drawing too bright a line.
And I don't really think iPhones are a Veblen good exactly. Targeted at higher-income buyers? Yes. Valued as much for design as aesthetics? Absolutely. But pretty sure a $500 iPhone would outsell an otherwise-identical $800 iPhone, nevertheless.
