First of all, none of this was lost to anyone who's done more than follow recent Internet influenced fads. Secondly the Kato video has been around for a long time. I'm not sure when Steve Elliot first put it on his web site but we used information from it in a WIA presentation more than four years ago and I know it was up for a couple years before that. Now people are holding up Kato's research saying from one side of their mouth, "See, this validates what a few people have claimed." From the other side of their mouth they're saying, "I get different results." Which is it? Either a cap iron starts to have some influence at .008" from the edge and good results at .004" from the edge like Kato found or his results are bunk. Which is it? Maybe I missed the thaumaturgy section?
No where is anyone talking about what's actually happening to the wood or what's influencing its behavior. How is that behavior different when using a double iron than when using a steeper pitch. No one is talking about the extra work of maintaining what is essentially two cutting edges for each plane iron. I tuned up a lot of old double iron planes over the years and used them in my work. No one is going to convince me that the wear I've seen and experienced on cap irons is anything but normal.
I'm amused at the thought of putting and identical camber on a fore plane's cap iron and iron then adjusting them for each depth of cut used. Are people trying to do woodworking with their planes or are they just tinkering with tools? Maybe everyone is still thinking every plane is a smooth plane?
I was up this same blind alley years ago. I decided I wanted the tools for woodworking and know where I ended up. Last time I watched a stampede up this blind alley I deleted about 3/4 of the woodworking forum bookmarks I had. I guess I wasn't thorough enough.