I concur.

The amount of useless emails has gone through the roof, with a lot of the content being managers reminding people they are still there.

Everyone cc's everyone now. If someone wrote an email to the ALL distribution group back in the day and there were more than 2 replies to that email, someone would immediately lose their shit and tell everyone to stop replying-all. Now those reply-all email chains happen weekly, with junior VPs laying hot takes all over the place.