I don't think kids will be outcast just because they don't own a smartphone. Based on what I can see around my own circle, most kids have 2 or 3 "close" friends

I don't think kids will be outcast just because they don't own a smartphone. Based on what I can see around my own circle, most kids have 2 or 3 "close" friends with rest being mostly varied degrees of acquaintances. Those friendships usually start one-on-one - maybe there will be some sly smiles and minor jibes/comments about the phone situation initially but then like everything else, people take it into the stride and both parties adjust to the "difficulties" pretty quickly and figure out workarounds within the limitation (or they don't and the friendship doesn't carry forward). Eventually the close circle forms where everyone has come to terms with the rough edges of everyone else. Like that one friend in the circle who doesn't have a smartphone. Also, providing "low-intensity" options like dumbphones just for messages/calling and laptops with age/time-restriction etc helps significantly.