Sorry but that sounds whacky, do you have any write ups on how the lack of the numpad increases the ergonomics?
All I have is in Dutch. There is some documentation from school (yes, school taught us about RSI) but also from a lot of patient interest groups (Reuma fonds, RSI-patiëntenvereniging), RSI specialists, physiotherapists, occupational therapists, "bedrijfsarts" (company doctor in English?) and so on. It is quite normal that people who have issues with their shoulder are issued these small keyboards. Usually they are from a Dutch company called Bakker Elkhuizen (probably better known here for their tablet riser they wanted to crowd fund). They have some
more info about this matter (it's in Dutch so use Google Translate; they do refer to other peoples research). Another more in-depth and medical look at it is from the Dutch RSI-patiëntenvereniging:
Keyboards (Dutch) and
mice (that first point looks very familiar doesn't it?

).
Another thing is that there is EU regulation about this matter. The exact details vary from EU member to EU member. In case of .nl there is a requirement concerning the keyboard where keys and layout should make operating the device easier/more comfortable. If you want to read more about it:
devices & furniture (Dutch only)
I mean if it really was an improvement on ergonomics, don't you think everyone else will be copying apple?
For the same reason why they are still selling keyboards with the same layout we had on typewriters (those layouts were about not having hammers get stuck due to quick typing, not about comfort), mechanical keyboards are a niche product and so on. Ergonomics isn't on top of the list when it comes to computers, every product that does have ergonomics in mind is a niche product. Just take a look at the price (rubber dome keyboard: 10 euro, mechanical version: 100 euro). Differently put: if I were going to spend that much money on something like an Apple keyboard it better be ergonomic! If not then it is no better then every other "cheap" product (Apple is actually on the higher end of the rubber dome spectrum) and those come at the fraction of the price you have to pay for the Apple keyboard.
Back in the 70s and 80s you didn't have keyboards with arrow keys or a numpad. They all were of the small type (not having arrow keys is the reason why vi/vim uses hjkl for moving around). IBM also had a small keyboard called the
SpaceSaver keyboard which also came without a numpad. There have been others throughout the years and among the keyboard aficionados the small keyboards are very popular (the most known one is the Happy Hacking Keyboard both the first and second version). Those are even smaller. There's a special name for the keyboards that are only lacking the numpad: tenkeyless (TKL). The reason we've gotten keyboards with numpads has to do with the increasing use of keyboards for accountants and the like, people who work a lot with digits. And what would be the most logical place for something like that? On the right because most people are right handed. At that time nobody knew anything about RSI. Luckily we also have separate numpads either wired or wireless (via BT).
We used to type on mechanical keyboards only until they came up with rubber dome. This was a welcome change in the very competitive PC market. The rubber dome switch allowed for much cheaper keyboards, you could buy 10 of those for just 1 mechanical one. That's why we have so many rubber dome ones and so little mechanical ones. It's not because they are better, they are far worse because the actuation point is at the very bottom. That means hitting the bottom of the keyboards continuously which is basically the same thing as driving your car into a wall. A lot of people have aching fingers due to this and couple with artritis this is even worse. Mechanical keyboards have the actuation point somewhere near the middle or the top which leaves space for you to stop the pressing down motion. That way you don't hit the bottom (aka you stop well before the wall).
TL;DR: quantity != quality and quantity != good ergonomics and quantity != comfort.
The fact that some of you are marking this as "whacky" is taletelling: most people have no idea about things like ergonomics, carpal tunnel syndrome, RSI and so on. They've simply never heard about it. In a computer driven society that is quite alarming.