I totally believe that you are right, but let me give you some perspective.
I picked this up in 2006, that was over 16 years ago now. I have 21 volumes of this manga at home in some box, cause when I started I was 15 and not even in high school yet and there was no internet community doing this full scale back then. I am now 32, finished high school, finished uni, lived in Japan for a couple of years and now I have a job. Since the 21st volume released back in 2011, we have gotten 7 volumes over 12 years, compare that to 21 volumes in 5 years. That's like a book every second year. I am not gonna reread this every 2 years to remember everything in the past 28 books. Most of us reading won't do that, we also no longer have time to do that.
I completely get that it makes sense if read in one fell swoop, but getting drip fed like this for 12 years... it's a miracle I remember anything of those 5 minutes I spent reading a chapter every 6-12 months.