Clearly text input with one hand and mouse input with the other is a better input paradigm, but it is still not in use much today.
I can't imagine that keeping my right hand idle for the once a minute or so I use the mouse is very efficient. I suspect the reason that it hasn't caught on is that heavy use of key-binds so that both hands can stay on the keyboard is the true "better input paradigm".
We're not talking about releasing a vulnerability that will compromise someone's e-mail. We're talking about a high risk vulnerability that could cost some random person their life.
The same thing could be said of many security flaws in industrial control systems. Out-of-control dams, water treatment plants, and nuclear reactors can all kill a lot more people. Until manufacturers are scared a few times by liability from high-profile exploits, they won't do anything about securing their products.
The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh