I doubt if 30 days qualify as short-time for anyone to download their photos from a photo-sharing service.
It's most likely that users use this service from their smartphones and so it's not like they are somehow going to miss the notifications they will keep sending perhaps every week your photos are still on their servers
> It's most likely that users use this service from their smartphones
So you're saying it's likely most of their users are completely unable to back up their photos at all? (since one of the top 2 smartphone OSes doesn't support downloading ZIP files, and the users of the other OS probably don't have enough free space on their MicroSD card)
Given that this is summer when many people are on vacation and have less or no Internet service and often the same for cell phone data service, which is famously limited anyway....
Also sad that Dropbox isn't investing in a migration story, though I saw Google do the same thing with Picnik when that was shutdown.