There might be other professions where people get more hung up on formalities but my partner works in a non-tech field and it's the same way there. She's far more likely to get an email dashed off with a sentence fragment or two than a long formal message. She has learned that short emails are more likely to be read and acted on as well.
The real cost isn't the tokens, it's the attention debt. Every CC'd person now has to triage whether any of those paragraphs contain an actual decision or action item. In my experience running multiple products, the signal-to-noise ratio in AI-drafted comms is brutal. The text looks professional, reads smoothly, but says almost nothing.
I've started treating any email over ~4 paragraphs the same way I treat Terms of Service — skim the first sentence of each paragraph and hope nothing important is buried in paragraph seven.
This is also the case for AI generated projects btw, the backend projects that I’ve been looking at often contains reimplementations of common functionality that already exists elsewhere, such as in-memory LRU caches when they should have just used a library.