Accurate Sibilants: The Ultimate Audio Challenge?

OK, I must admit that I am really sensitive to how any system I'm listening to reproduces sibilants, but I continue to be shocked at just how drastically different recordings and live feeds reproduce this problematic frequency range. For example, I listen to a lot of BBC Radio 3 and Minnesota Classical streams; the Minnesota stream captures vocal sibilants utterly naturally...silky and smooth. BBC Radio 3, though, will practically tear your ears off with harsh -ssss sounds. And the same goes for every recording, with one of the single biggest challenges for any recording mix engineer being sibilants that are natural and integrated into the rest of the voice. My question is this: With all of the advances in recording technology, why do so many recordings and live streaming feeds continue to reproduce vocal sibilants that are harsh, gritty, and sound absolutely nothing like they do in real life when we don't seem to have nearly the same problem with other instruments?