Again, I ask you if you have kids.? Let's say you are right, and some new technology comes out that is all voice. That is not going to happen for a couple of years at least.
And voice text is almost as bad as text. It still distracting. Our apps will be have to then evolve to disable voice text.
The reason kids and people text is that they do not want to , or have time to have a full voice conversation. They LOVE texting. Texting is great for times when voice is not ALLOWED, such as in class, in a car when you don't want anyone to hear your conversation, and even movie theatres. They all do it. Kids and adults.