Well, there is some sharing (PhotoStream), but you are right in general. And even if Google is 5 years ahead (I don't think they are), and I do use google services for sharing, the thing is I don't enjoy it. Functionality is there, but experience is lacking, alas I cannot pinpoint why. Just every time I use Google docs or Google drive I want to get out as soon as possible. For this reason I don't see Apples lack of these services as a big problem and I don't see Googles offer as a big advantage. It is possible, however, that with right implementation it may become a necessity.