I've never understood how the Janko keyboard is employed although I've seen videos of people playing them - seems real easy - so easy that it makes me wonder why it was never adopted by the pianomakers.
I guess that they had already refined production of the keyboard as we know it today so that any change would be atrociously expensive for them. But the more people that know Janko, the more the demand and thus a market is born for Janko and the pianobuilder who captures that market will make a nice living until others jump on the bandwagon.
So really its more than just initial price - its about competing values...
Here's a site with an electric Janko keyboard:
http://images.google.com/imgres?img...o+keyboard&svnum=100&um=1&hl=en&safe=off&sa=N