Being the #forevercynic, Instagram's game is completely transparent, I think.
How to stop haemorrhaging users to Snapchat and address the issues plaguing its model and pushing users there - diminishing authenticity, immediacy, locality? Its answer appears so bold it was previously unimaginable. Whereas platforms innovate stay relevant, Instagram's answer seems to be to reinnovate, and provide users... basically Snapchat. Except with a better user interface.
Instagram's strategy appears then to be deviously simple - if my users are using my platform as a springboard to Snapchat (count the number of "Find me on Snapchat" posts), why not offer the same features whilst I still have the advantage of having the greater reach and larger member base? The worse case scenario is users post the same thing on both platforms (you can upload saved photos and videos). And overtime, as the other platform becomes irrelevant, users will abandon it.
The primary/secondary feed currently feels hastily implemented, and the app is still rather buggy. It will be rather interesting to see how this pans out... So I guess, it's on to Snapchat to make their next move.