They obviously did not want to end the character's life, maybe in hopes Kristian would return, or perhaps they would recast. The thing is...Bo & Hope were THE couple. Any other pairings for either character never worked. Bo & Hope are now grandparents. They have aged as we all have. The same kind of stories from the 80s & 90s would not work for them any more. Jack,Jen... grandparents. Kate, is a great-gramma, Contrast Tom & Alice as grandparents with how the ones today are written. We saw how Stefano, as he got older, wasn't as agile, we see Victor currently. I am grateful that we have as many characters still being portrayed by their originators. Heck, Roman was recast, & has been in that part for wayyyy more years than the actor who originated the character as that was only two years.
I was very fortunate years ago, to have seen Carol Channing on stage, starring in Hello Dolly! Since then, I have seen Ginger Rogers in that role, also Pearl Bailey. And then local community theater as well.
ALL TV shows run into recasting when an actor decides to leave, and is adamant about not returning. Days has had to deal with Peter Reckell decision to leave, (Bo), Kristian Alfonso, (Hope) Kate Mansi (Abby), Melissa Reeves (Jennifer), James Scott (EJ) Alison Sweeney (Sami...tho they do get her back for short periods every year or two...but it makes it difficult to write current story for her, based on what transpired previously...) And there are more.
Heck, NCIS has lost Mark Harmon, the wonderful Gibbs, and has to replace.
A few actors have left, but did return, tho who knows for how long......Carmila Banus (Gabi), Jay Kenneth Johnson (Philip), Tony & Anna seem to come and go, thankfully the actors agree to the recurring status.
Sometimes, the recast just doesn't work, but most times, works out very well.