That seems a bit dubious, can you point to any research which backs up this statement? Intuitively it seems to me like you would need to be switching input devices extremely often to avoid RSI (as in, once every few MINUTES rather than every few months).
Personally, the only real solution to fix RSI has been strength training & regular breaks during work.
I'd love to find some authoritative papers on the subject but this is based on 40 years of experience with the subject of computing and RSI, and I have never had any reason to question it because it works for me and was the best advice I ever got from a physiotherapist: change your keyboard often and you'll avoid RSI.
It works, that's all I can say about it. RSI problems go away whenever I switch keyboard/mouse setups.
I'm in the same boat as you. I regularily switch between high and low keyboards, high and low profile mice, different keyboards/mice at work/home and in addition I switch between right and left handed mouse whenever I feel like it, sometimes even several times an hour. At one point I had two mice at on my desk and grabbed the one which hand was free at the moment. Never had RSI in my 30+ years of active computing though this doesn't prove anything, maybe I'm just lucky. But still, I find it quite liberating to not depend on your must-have setup.
I've reached the point where I can basically work with everything thrown at me. I have preferences, yes, but I'm not the type of person who has to have perfect setup or else nothing gets done.
This has not been my experience at all. For me, I had hand and wrist issues until I stuck with an ergonomic keyboard (Kinesis Advantage2). It's been like 6-7 years now and I've had no problems since.
I've used an Imak Smartglove w/ Thumb for more than a dozen years. It helps a lot. Also a Kensington Expert Mouse, a keyboard tray, and a Steelcase Leap v2.
Personally, the only real solution to fix RSI has been strength training & regular breaks during work.