You were essentially implying that studio leadership forced the team to abandon Killzone to focus on Horizon, while you could already tell from Shadow Fall (and 3) that Guerrilla wasn't particularly fond of the series anymore and wanted to move on to new stuff, which ended up being a much better game on Zero Dawn.
Also, variety? It's not like Guerrilla had any varied output pre-2017, and this is ignoring the fact that most studios out there only work on 1 game/series. Weird thing to judge Guerrilla on.
Guerrilla Games didn't want to make more Killzone games, that's the hard truth.