It depends on how you define "friend."

I don't require that my friends have any interest in me outside of the contexts they wish to be friends with me in, though, and so I do consider work friends actual friends.

Same thing with cycling friends, childrearing friends, and hanging out and drinking friends.

Why should a friend share extra time with me for some reason? In any case, the more time you spend with contextual friends the greater the likelihood you will meet a lifelong friend.