There's also the problem (for me, and I have observed for others) that emails sent to lists or large numbers of recipients/CCs automatically get less attention

There's also the problem (for me, and I have observed for others) that emails sent to lists or large numbers of recipients/CCs automatically get less attention and priority than emails sent to me individually. If I get an "all hands" type of group email, I skim it, or maybe just read the subject line, depending on who it's from. Over time I've learned that there's almost never anything directly actionable for me in these messages. The day is too short and there's too much to do to spend time carefully reading long-winded broadcast messages.