Either rely upon everyone else changing their behavior, or give up and use your LLM to re-compress incoming messages to be informationally dense as you see fit.

It's lossy tho. LLMs are crap at picking the "good stuff". Eg: the summary of the email covered the point about the family event but missed that the deal-terms were moving from Wyoming to Delaware.

Personally, I'm confident with my level of output so I'll continue to dutifully read all the crap that gets sent to me on company time. I'll just prefer to engage with people who communicate well and encourage that in others.