Honestly the theme is that players are prone to getting certain exotics through engrams, while certain exotics are left out of their loot table drops. That's why you hear of some people getting zhalo supercell non stop but never getting a telesto. And other players will get telesto non stop but never get a supercell. (Me) My assumption is that the RNG is designed like that to keep players always chasing the dragon. If you understand the saying. Basically playing with the hopes and dreams of getting something that just isn't gonna happen. Just one more try tho. ..