Is that due to the layout itself or the fact that you are a) probably spending more time practicing (or at least focusing on improving) and b) unlearning bad habits you may have had when typing QWERTY?

Everybody is different, but there are plenty of people that type faster than 85 WPM with QWERTY.

Also, I'm not saying there's no reason to switch. I can believe some alternative layouts are more comfortable and/or better for your hands (these are far more important than raw speed, anyway). I'm just not convinced on the claims as to the size of improvements.

Either way, I can totally get behind self-improvement.