Here's my elitist opinion: big brands don't sell ergonomic keyboards, only cynical marketing ploys using that term, if any. Keyboards are bad, you have to face it. Real ergonomic input devices are economically not viable because they are too alien and have a learning curve. They learned that in the nineties. Bigcorp won't touch it. For example, look at this special DataHand prototype for HP. That would have been nice, the HP DataHand. Except that no deal was made.
Bigcorp only sells wavy keyboards to the sheeple which you champion. Bigcorp gets your money, you don't get an ergonomic solution, but perhaps you feel better with your placebo.
Big corps don't sell the obscure, high end ergonomic keyboards, no. But in the case of the MS Natural line, I find it is indeed more ergonomic than a standard keyboard. It's not the most ergonomic thing in the world, but the fact is that I, and others I know, found it more comfortable than a standard keyboard. And no, it wasn't placebo in my case. I found straight keyboards uncomfortable to use for long periods of time pretty much from the point my growth spurt ended as a kid. The Natural series allowed me to type longer with less discomfort right off the bat, and many years down the line that remained the case.
I didn't even know about those little known and expensive brands back then. I, like the vast majority of people, was not researching keyboards left and right for a hobby. The fact that a big name like Microsoft made it was the only reason I got exposure to the concept in the first place. Even if I did know of the more expensive ones, I sure as hell wouldn't have bought a multi-hundred dollar keyboard back then as a teenager. More accurately, I couldn't have afforded one.
Flash forward a decade or so, and here I am with a Kinesis and an interest in something like the DataHand. I'm not a unique case in that either. A friend who I introduced to the 4k is actually curious about higher end ergonomic boards, and even with changing to an alternative key layout.
Call me a champion of sheeple, or whatever, but I am a firm believer in the learning to crawl before you walk sort of logic. People don't have to be exposed to the best thing right away, and not everybody is brain dead enough to assume that what they have is the ultimate device of that type when marketing says so (Apple syndrome).
That said, I'd obviously like it if there were more attempts at ergonomic designs from the big players. And no, I don't count the wave designs as an attempt.