As an aside, Blizzard has never supported players targeting gear and has largely been pretty salty about the idea of “BiS” in general. Blizzard has always been about the RNG.
That said, Blizzard’s RNG is breathtakingly lackluster and lacks nuance. Because at the end of the day, it is still pure RNG for each time you kill that boss. So while statistically, the chances of you getting the same drop each week should decrease, at the end of the day, at that moment, you still are subject to the absolute %drop listed in the loot table.
What Blizzard needs to build into their RNG is a soft layer of “bad luck protection” in which it calculates how often a specific item drops and simply modifies the chances that something else on that loot table for you drops instead once you pass a threshold.