After the recent breaches in Facebook and the data that hackers have stolen, I don't believe that Zuckerberg is capable of protecting our privacy.
And I also think that he indeed doesn't want the full privacy because if that happens then he will probably lose data from the users and he wouldn't be able to "feed" his AI algorithms with userdata.
Just IMHO but for most people shouldn't really care about those hacks until hackers are able to get your private messages (which did not happened as I know). Most of the other data may only be used for different kinds of online advertisment and worth really nothing.
What we need is a blockchain based messaging app.
These guys
https://bizzpro.co have something promising but we still need to see if they can deliver the full thing before Facebook launches its own token.
We already got Telegram and everything seems to be fine with it.
At the current stage Facebook became an unusable piece of shit that can only be used as a newsfeed. There is no point in trying to make a better messenger.
Also, their own coin would be the same centralized garbage. After reading this thread do you really believe that they may do something related with an increased privacy?