It is true that some of these apps have served a temporary service to people who needed to communicate without government interference.But all these apps suffer from the same chicken-and-egg problems:
You need to download and install them before they become illegal, and before they are necessary. Most people are too lazy time efficient to be thinking so far ahead, and don't even have a go-bag in their home. They only work if the person you want to talk to is also using it. And why would he? Other chat apps like Signal and Whatsapp work just fine, don't they?
It's not purely bearish. They suggest some ways they might succeed. I also think that lots of things end up working eventually despite lots of prior failures.