They probably can tune for it, but it is not what the shareholders want anyway. I am unaware of any frontier lab who is actually interested in building something like that, long form proza indistinguishable from humans. Automated code and low hallucination rates are more important topics, and trade-offs need to be made.

Edit: why the style is like marketing corp-speak has to do with personalization not working well yet. So the default vanilla style is very corp. Most chatbots allow you to change the system prompt though and that can get rid of a lot of these issues in a lot of chatbots. But it is hard to maintain such a system prompt as the bots change so quickly.