I have a guess about these guys who are complaining that they didn't get "a single pink" on their way to 55. I think they leveled to 53 in CtK, and used 3x XP potions for their last 2 levels, which would mean that they only got about 50 chances for a drop. See, you end up clearing about 85 mobs in Hideout, at yellow threat that is 147 xp which tripled is 441. So even if you conservatively round it down to 400, you would only need 20 runs or so per level for levels 54 and 55.
The drop rate for pinks is low, maybe less than 1%, so ... no wonder they aren't getting pinks.