There is probably a case for beech being beating up a 26 degree plane iron edge, and softwood not doing it.
i don't work much with softwoods and one of the things that I had some displeasure with was using japanese planes for a while and finding that keeping the edges free of defects in even cherry was not always easy. in an 8/10bu plane, if you go to 30 degrees total angle, you're already butting up against clearance-related longevity issues (though it's better than honing out damage).
I vaguely recall some of the old stanley instructions suggesting 25 degrees, and some suggesting 30. The soft irons in some of the early planes probably wouldn't have fared well at 25 degrees (I have a pack of NOS 18 block plane irons, and they are definitely on the soft side), but in pine, it may not have been a big problem.
All of this is why I can only claim to have observed things in this test with this wood and with the plane used, and because I have done all of this testing with the house O1 in the LN smoother rather than suddenly switching to the hock iron. Hock's iron is a bit harder, and mine is a bit tougher. In beech, it seems that they're an even match.
if bill wants to test the iron I've made for hardness, I can send it when done here (I have another one and won't go through withdrawal). Otherwise, I can guess at it in the paper.