And they see it so feasible, that there are those who have sent emails to Apple executives asking if Face ID is going to facilitate those multiple profiles. And recently one of those emails has been answered by Craig Federighi, who makes it quite clear: Face ID is for one person.
One person per device
The argument of who has written the email is that, with Touch ID, you can set several fingers to unlock a device regardless of the person they are. So, for example, two married people can have mutual access to their phones or a father or mother can access their child's iPhone.
But Craig is blunt: the idea with Touch ID was not to do that but only the owner scanned his fingers to unlock the terminal. And with Face ID the same thing will happen. And that, in turn, makes us see very, very unlikely the possibility of iOS becoming a multi-user one day.