> I’d argue that a well-written email is one that doesn’t require a summary.

I strongly agree. This echoes the cartoon about using LLMs to write and then summarize emails (https://marketoonist.com/2023/03/ai-written-ai-read.html).

If someone doesn't care enough about my time to compose a well-written email, with a tl;dr at the top if necessary, then I see no reason to care about what they've generated.