I think if you read the announcement carefully, it is the standard aqui-hire wording. Dropbox isn't remotely in the same space as PiCloud, and doesn't want to be. They simply "acquired" PiCloud to get their team of developers, which is why they're fine with open sourcing PiCloud. They won't even be using it internally.

   the team has decided to join Dropbox... 
   We’ll be bringing our API-building expertise to the Dropbox Platform, ... 
   Even though the team is moving on ...

I also hope that Multyvac will be a success. That said, I hope they'll start communicating soon. I can't really judge if they'll be able to be a success... but I hope so.