Sounds like absurdly poor luck, then.
I couldn't find the drop rates online so I don't know exactly how poor my luck was, but if grinding is gonna be like this and be skewed to RNG rather than skill of fighting with said enemy you grind, I'm just gonna play through Normal and not bother with Hard.
First off I'll say this: RNG and grinding are my top 2 hated things in video games, so my opinion is going to be very one-sided. (I now question why I got this game, oh right, I was told it's fun by someone who hates grinding.)
With that out of the way...
Having drop rates increase per elite you kill might be a solution, maybe by 1.25x the base amount. (For example, 1% drop turns into, per elite kill, 1.25%, 1.5%, 1.75%, etc.)
This would of course reset when you leave the room or die.
Ideally, the drop would be pretty much a guaranteed drop around when the grinding turns boring, probably around 12 hours. (8 is for people like me who hate grinding, so I'd assume 12 is better.)
Grinding shouldn't completely disappear, as it is fun, but to a certain extent it becomes stale, like watching the same funny youtube video over and over.