There's RNG that gives you at least something, and there's RNG that gives you nothing time after time. Yes, there are examples when you couldn't get precious bis trinket. But at least you had limited tries to get it: "no bis drop - maybe next week - no bis drop - maybe next week - oh, cool, other boss dropped nice trinket - no bis drop .... oh, twenty weeks have passed, now's new tier and new bis trinket". Now with legendaries you have "no drops" thousand of times (and could have WRONG drops at the start of Legion, meaning your character was fucked as no new leggos would drop).