[a-priori]

Sure. I've used Dvorak about 99% of the time since about 2001-2002. Except on my phone; I use QWERTY there, because it's a completely separate skill and the different layouts don't make any difference when you're typing one-fingered (Android's Gesture typing). I actually just tried switching and typing a few sentences, and I keep defaulting to QWERTY gestures.

I can still type QWERTY if I need to, even though I have barely used it in the past 13 years or so, but it takes me a few minutes to adjust and get up to speed. This happens if I need to use someone else's machine, which doesn't happen a lot. They wonder why I'm suddenly typing like an orangutan. But it goes away after maybe 10 minutes, then I'm up to maybe 70% of my Dvorak speed which is good enough for most short-term purposes. It still feels awkward to type QWERTY, so I try not to do it for more than a couple minutes.

(Interestingly, most of the problem when switching comes from punctuation, the muscle memory for typing punctuation seems to be separate in the brain. I noticed this when I was first learning Dvorak. I'd type 'v' instead of periods all the time, even when I was reasonably fluent with typing letters. Now the same thing happens in reverse, where I'll type 'e' or 'w' instead of periods or commas if I'm typing QWERTY.)

Overall, the fact that I'm using a different keyboard layout isn't something that I think about much. I'd be surprised if I'd even thought about it more than twice in the last six months.