Let's say that it takes a couple of years of retraining from QWERTY to Dvorak until a typical user can reach a 10% improvement. How much typing will they have to do in order to regain that lost time?
Typing, nowadays, isn't the bottleneck. If we still had pools of typists clattering away to reproduce our words then - yes - a more efficient typing standard could be good. But what we have is good enough and the gains just aren't sufficient.
Having two concurrent standards is a nightmare from a usability point of view. I'm sure you've had the experience of using, say, a train ticket booking system which insists that you use a A-Z keyboard. You are slow and frustrated.
I live in a country which hasn't fully embraced the metric system - so people flit around between metric and imperial to all sorts of confusion.
Should we all learn Esperanto? Should we all switch to 220V electricity? Should we all use decimal time? All of those standards are better - but they're not good enough to warrant the upheaval of switching.
There _is_ significant improvement between QWERTY and Dvorak, and I covered them in my question (just did not bother with links, but I can bother if the question will be popular). This difference is much deeper than difference between RHD and LHD, because as for cars there is better to have one standard for every country than two standarts, no matter what standard it is. And as for keyboard layout, we _already_ have one standard - but since it has been produced for reasons different from efficiency of typing, my opinion is that it must be changed for more efficient one.
Nothing can stop me from using Dvorak, you are right, and I even do not need another hardware keyboard for this reason. But my question is about future generations of typers. I am interested in getting rid of needness of learning bad layout, which occurs mandatory. I am seing very similar situation in the "experiment with monkeys and bananas" and this experiment is irrelevant to RHD vs LHD problem. Do you really think that we must use inefficient standard before the end of civilisation, having a better one but ignoring? For the sake of...?