Your implication that productivity increases with more exclusive use of the keyboard against all other input devices, is dubious. See: https://en.wikipedia.org/wiki/Mouse_chording, and programs where it is put to good use (acme).
http://ux.stackexchange.com/questions/30682/are-there-any-re... gives some more recent studies on the subject. I haven't read them, but it seems to me that keyboarding can be faster than mousing if you do it very, very, often.
And of course, the quality of mouse and keyboard matters a lot, too (early Windows mice were bad compared to Mac mice, mostly due to software (I have seen Windows mice were it was impossible to address every pixel on the screen, possibly due to staircasing/aliasing (what does one call that?) in the conversion between coordinate systems); this reminds me of http://www.folklore.org/StoryView.py?story=Shut_Up.txt, which isn't really related, but may be an interesting read, anyways)