The Salvatore brothers had a good reason for being "bitter," as Ian Somerhalder put it during Wizard World Philadelphia 2019. It came from a place of love for the stars TVD lost to the new show.
The topic came up when Ian Somerhalder was asked to name his favorite "K" villain from The Vampire Diaries -- Katherine, Klaus, or Kai? First of all, I love that question. Second, I love how he began his answer:
They were all amazing on their own. Klaus really ticked me off 'cause he left and went and got his own show. Rude. Oh my gosh, we -- by 'we' I mean Paul and I -- were so bitter with The Originals because we lost all of these amazing actors. Like, those were our peeps, dog. Plus, they had all those great accents. ... Klaus was an amazing -- Joseph Morgan is an insanely beautiful actor.
Yeah, if I lost the chance to work with Joseph Morgan every day I'd be bitter, too. Morgan joined The Vampire Diaries as Klaus Mikaelson in Season 2, and was a main character in Season 3 and Season 4.
However, in October 2013, The CW gave Joseph Morgan's Klaus and family their own spinoff in The Originals. The Originals premiered right after the first episode of The Vampire Diaries Season 5. Stars and characters like Daniel Gillies as Elijah Mikaelson, Claire Holt as Rebekah Mikaelson, and Phoebe Tonkin as Hayley Marshall were suddenly gone from the flagship vampire show.
The Originals went on for five of its own seasons before ending last summer 2019. (It took until the final season to get Candice King's Caroline on there for an unsatisfactory reunion with Klaus. Talk about bitter. Klaroline deserved better!) Right after The Originals ended, Klaus Mikaelson's daughter Hope Mikaelson (Danielle Rose Russell) got her own spinoff in Legacies, which is basically the love child of The Vampire Diaries and The Originals.
So I'd say this all has a happy ending. And there was enough crossover between the two shows to keep the Mikaelson family alive (so to speak) on The Vampire Diaries. That's still happening now with past characters from Vampire Diaries and The Originals popping up on Legacies.
Each series has been able to stand on its own two feet, and sometimes fans end up preferring the spinoffs to the show that started it all. When Legacies Season 1 hit Netflix, some fans even said they started there and went back to watch The Vampire Diaries and The Originals to understand all of the many references to the mothership shows.
One year out from The Originals finale, and two years out from The Vampire Diaries' ending, the stars have all moved on. Paul Wesley returned to Mystic Falls to direct an episode of Legacies Season 1, but he has his own new series now. Ian Somerhalder is working on another vampire show, V-Wars, where he is not the vampire. And Joseph Morgan just announced his first major TV role since ending his run as Klaus.
By the way, Ian Somerhalder eventually did answer that fan question from the Wizard World Philadelphia panel. He picked Kai, and I want to talk about that another time because it could/should directly tie into what's ahead in Legacies Season 2, which premieres this October 2019. Until next time, stay unbitter. (UPDATE: I'm ready to talk about Kai, so here's that next time.)