YMMV but after 3-4 weeks of dvorak, I actually did have difficulties when using qwerty. I gave up dvorak because I don't want to have to modify every keyboard/system I'm on, as opposed to just sitting down at a terminal and getting work done.
I think you might have tried a bit more. I'm typing this on my wife's qwerty laptop and have zero issues with blind typing on it, just a little more strain from having to move fingers more that it is possible on Dvorak.