I do note that you conflate two distinct issues: whether touch-typing is worth learning, and whether Dvorak is a meaningful (or any) improvement over QWERTY. I am definitely far more suspicious of the latter claim than the former (see my link in the grandparent for a thorough debunking).
Even the studies cited by the author in your link show a speed advantage of around 5% for Dvorak over Qwerty. Considering my point of the 10k hours, the payoff is more than worthwhile, before even taking RSI into consideration.
On a side note, one of the reasons I decided to learn touch-typing was because I have some free time at the moment and was looking for something else to do than read blog posts all day, so I totally agree with you that investing 30-40 hours now might not be the best for everyone... TDT probably recommends it though.
While we don't spend all our time in front of a computer typing, it does seem to represent a non negligible portion of our days. Assuming an hour a day of typing on average for the rest of your life, the time you will spend typing is tens of thousands of hours.
I'm currently learning Dvorak and it looks like it's going to take about 30-40 hours to be able to type properly. So the gains in efficiency don't have to be very significant to pay off.
To check how efficient the time investment is I checked my typing speed. Like you, probably, I'm not a touch typer but I felt like I was typing pretty decently before, and measured at 40 wpm on both of the two websites that I tried, with no mistakes. I'll check my speeds with Dvorak once I'm done with the lessons, and again after a few months of practice, to settle this debate hopefully, but just from having done the first ten or so lessons I can already see that Dvorak is going to be a major improvement, if not in speed, definitely in terms of comfort.
After having finished the basic course in Dvorak and touch typing for a few weeks now, here is an update on my results: I spent a total of 30 hours learning to touch type, but even once I could touch type properly, I was still really slow, at about 20 wpm immediately after finishing the lessons, half of my original speed. Ten days later, after forcing myself to avoid the QWERTY layout which resulted in some inconvenience, in particular with keyboard shortcuts, I am now typing at about 30 wpm in Dvorak, which is still significantly slower than my previous, unconventional but obviously not so bad, typing in QWERTY.
The idea that I will probably spend tens of thousands of hours typing in my life still stands, though, and the touch typing is getting more and more natural each day, I'll try to update my results again after several months to see if there is actually a significant increase in typing speed over the long run.
On a side note, comfort is definitely better when touch typing "properly" in Dvorak than when typing "improperly" but faster in QWERTY, however this may be related to the way I positioned my hands on the keyboard rather than to the initial keyboard layout.