The Iconic Mythics saga in Diablo 4 just won't end, and as Blizzard continues to step on rakes to the wide ridicule of the game's most hardcore fans, the devs have announced that they're looking into how to escape the rake field they now seem to permanently reside in. In less hyperbolic terms – yes, they know Iconic Mythics aren't dropping, and yes, they're trying to figure out a solution.
A recent update was meant to actually get Iconic Mythics dropping again, as the patch notes promised that Blizzard had "increased the chance of naturally dropped Mythics being an Iconic Mythic." By all accounts, however, they're still effectively impossible to farm.