Tutanota has a subpar UI/UX, and people like shiny. You won't get the masses with that.
DDG is valiant, but doesn't give the same "read my mind" feeling that Google has people used to. I see few people stick with it due to this.
Signal has proven itself as a great product in many ways, but people opt for the convenience that other messengers provide. The Signal crew seems to understand this, though, and slowly be working towards ways to match that. They'll (eventually, IMO) succeed for this reason - more "privacy respecting" entities need to take this route and understand that you will not get users or attention solely on espousing privacy rights.
DDG is valiant, but doesn't give the same "read my mind" feeling that Google has people used to. I see few people stick with it due to this.
Signal has proven itself as a great product in many ways, but people opt for the convenience that other messengers provide. The Signal crew seems to understand this, though, and slowly be working towards ways to match that. They'll (eventually, IMO) succeed for this reason - more "privacy respecting" entities need to take this route and understand that you will not get users or attention solely on espousing privacy rights.