you could have just said
If you want to be reductive about it, sure.
I think the tragedy of Hou Ken is worth expounding on though, because that's what his story was. A tragedy.
Just think about how fucked up his story was:
He was raised by his parents' murderer who stripped him of his humanity and molded him into a bloodthirsty warrior-monk who had nothing but pain and loneliness, and the mission. A killing machine for all intents and purposes.
And following those beliefs he had been indoctrinated with practically since birth, Hou Ken denied himself all the joy and beauty life had to offer for the sake of achieving some kind of pinnacle, some kind of transcendence that could usher mankind into enlightenment.
Hou Ken lived, trained, meditated, fought and killed believing in nothing but his mission - only to see a similar kind of strength he was searching for in a young man who wasn't even looking for it
It broke his mind, and how could it not? There he stood, knowing all he had believed in to be a lie and all he sacrificed to be for nothing. Hou Ken was stripped of the last thing he had with a semblance of positivity - his belief.
He began to doubt not only himself - he had done that before and resolved to get stronger - but in the validity of his beliefs. In the futility of his mission. In the truth of his teachings.
That doubt was the little death that preceded.
Hou Ken was dead before Shin's glaive fell.
But, yeah, the guy lost because of friendship, sure.