That's possible and maybe we have to go with that to fit what we saw onscreen. But I'm not sure that mass casualties and chaos would produce more similarities. Seems like more chaos would create more diversification. But who knows.The culture may have degraded in complexity since Qo'noS was left uninhabitable by the Burn. 125 years of reduced contact with the rest of the galaxy, mass casualties and political chaos and you might have a Klingon society that just isn't what it used to be.
I just know I rolled my eyes the end of the episode.

