Yes. As we all know, removing a feature from an existing, still-supported product is exactly the same as discontinuing a product entirely without notice.

Sets in spreadsheets still works for me. Edit: When the feature was "retired", there was a note that it would be replaced with a better version. https://support.google.com/drive/answer/3543688

Well, that's not surprising given that it was never a documented feature to begin with, to my knowledge.

Unless I'm missing something, that's talking about the standard autofill functionality which still exists.