Russell, you might be underestimating the "poor user" :-) But I'd be
tickled pink if we could all buy standard-sized, non-adjustable units.

It might come down to how much variation there is in phalanx length
and proportion. If all our finger bones scale together in constant
ratios as our hands get bigger generally then it seems like it will be
easier to use standard-sized keyboards.

From a strictly commercial viewpoint there are some advantages to
adjustability --- logistics are simplified, inventories are reduced,
etc. One wonders also whether we'd need men's and women's sizes as we
have with gloves.