Taskers are a level 60 item, so low-level gambling like for the Necro ring doesn't make sense. It's just RNG. And Taskers are a rare pair of gloves, so it'll take a lot of shards: on average 10k, and even after 23k shards there's still a 10% chance of not getting it.
It's all RNG
I'm gonna lock this since otherwise those threads usually derive into a list of everyone telling their RNG story, and we already have a thread for that.