Most of you probably do not care for achievements so you are thinking 'well its a collectible for a reason' blah blah blah. Hear me out on this because the drop percentages are a little ridiculous. Right now I'm grinding mobs hours and days on end to get one single piece for this achievement (because achievements are what keep me busy in this game and keep me learning new things). Like I said though, it is ridiculously low for people to grind hours on end for a collectible which has a drop chance of 0.1 - 0.8.
https://en.uesp.net/wiki/Online:Chitin_Accumulator
If you take a look at that link, I think it is safe to say that you could go through thousands of mobs and waste an entire week just to find one piece if you're lucky. I am pretty sure I am the only current player who actually wants to go after these trophy achievements just because of hunting and being a completion-ist. This is only one of the trophies and there are many like it. I would say the drop chances should not be in the 0.X but should be somewhere near the X.0-10.0 percentile. It is a lot of overlooked content because no normal player actually goes to these farming spots and spends hours here. You need someone who would take the time out of their day to go waste doing this which I personally think that if someone should do this, it should be somewhat more achievable.
Maybe this is a useless rant because I'm tired of running circles in a delve and just complaining but it seems a little too low for people to want to go for unless they're die-hard achievement hunters.