You might be overestimating the actual observable effects "ergonomic" keyboards have over traditional designs. I wouldn't make a confident ergonomic claim for either type of keyboard, but I'm very skeptical that ergonomic keyboards on average provide observable health benefits. And, anecdotally, I've never had any health problems related to ergonomics (26 years old, 8+ hours a day at a computer desk for at least the last 10 years).