I know you're getting grief, but I completely agree. Size and strength aren't the same in terms of muscles, so it's quite possible for small players like Silva or Sterling to be strong enough to compete with bigger players.
Add in that using your strength, in the way you hold your body, anticipate contact and brace yourself all comes from experience - and you're going to get more experience of it when you're playing against older/stronger guys - then he can definitely improve.
It's often the case that younger players are used on the wings as they can run into space without needing to hold the ball up as much. At City that's not easy as you're expected to control possession wherever you are, and even on the wing, Foden struggled for a long time with the physicality of older pros.