Flickr could have been Instagram and more if it hadn't been neglected for so long. I've renewed my Flickr Pro subscription for a year - it's an acceptable gamble at this point. I have no alternative for the service.
Except that's sort of my point. I don't much care about Instragram. I just accept that there's no unicorn photo service for people like me. If flickr goes down, I'd probably switch to Smugmug.