One piece is the problem..
Here's the issue we're trying to solve.
Ergonomics..
With respect to keyboarding, there are MANY factors which fluctuate between different people and even FOR a single person. Which is to say There is no one size fits all..
So by making a keyboard 1 piece, it sacrifices a significant amount of adjustability.
WHY would you want an adjustable keyboard..
How tall is a person..
How high is his desk..
How high is his chair..
How far does he sit in that chair,
How close does he sit to the keyboard.
How long is the keyboard tray,
At what angle does his wrist enter neutral position.
What angle does his elbow make with his trunk,
How far apart are his shoulders..
Is the person Tired, and Slouching in his chair
Is the person awake, and sitting upright
You can only do so much from the chair, and table ..
Short of buying all new office furniture, MOST people won't be able to adjust from that end.
SOOOoooo.. How do we come by a Keyboard that actually Suits your environment..
2 Piece, Multi-Axis tenting adjustable.
Ie... ERGODOX
ANY and ALL one piece ergonomic solution will fail to compensate for the myriad of unadjustable use-cases.