Well I guess they just don’t think it is necessary to have a n-ary tree. I use i3 but I rarely have more than 2 windows open per monitor (apart from my floating scratchpad terminal). Usually I have just two windows side by side per workspace. So if I would switch to bspwm I wouldn’t really be limited by it. That is also my reason for not switching to a dynamic tiler: I never split my windows enough to where it matters.