What happened to Holly Hocks once Bo-Jack read that letter she gave to him?
It's heavily implied that the letter is HollyHocks way of cutting Bojack out of her life. Most likely why we never see her again, the fact that Bojack doesn't cry or mention her in anyway means it most likely was not suicide. Take this with salt though as I don't 100% know, just my best guess
That's one of the dead-ends. They only had so many episodes and they had to prioritize who gets the most screentime. That's what Hollyhock got. Yeah, I also feel that the whole Penny story is rather unfinished(seeing how her mother warned her about not getting involved), and that Hollyhock was given the "easy way out". Obviously she was already aware of S6E8, and probably has seen both interviews, but... When the show introduced her, it made it very clear that she IS Horseman. Of all the characters - she was the closest to someone understanding him, because she is also a mean, fat slob at her core. If the show had time - these sentiments could very well be illustrated properly, but they've settled for the letter. Honestly... season 6 should've had just 12 episodes that would culimate with the interviews. The true fallout would take an entire season 7. But they had to cram it all into 8 episodes, that's what we got.
I agree with Wrathinside that the whole of Season 6 feels super-rushed. But at least they got a heads-up that Season 6 would be their last season. Otherwise, the show would have been even more unfinished.
What do you think?