The Financial Times, citing a study by advertising technology data platform Attain, reports that 34% of Americans who were born after 1996, use iPhones. At the same time, the share of people of the same age who use Samsung smartphones is only 10%.

Apple has a much stronger ecosystem: iPhone users buy Apple Watches, Macbooks and Airpods. For example, for every hundred handsets, according to Canalys, 26 iPads, 17 Apple Watches and 35 pairs of AirPods are purchased. Samsung's numbers are three to six times lower.
One reason is digital ostracism: people will simply be jilted if they have Android. There's the awkwardness of seeing a green bubble on iMessage, and even the refusal to date if a guy has Android. Many won't even respond to messages if they're green.
Basically, it's now clear why Google has no way to get Apple to switch to RCS - in this case, messages sent from Android won't give the user away, and therefore they won't be rebuked for chatting. Funny: iMessage has become a major competitive factor!
Interestingly, the older generations have reached a balance - here the share of iOS and Android is about equal.