at that scale i don't believe it is possible to do much better on this particular issue at least.
replyMake email reputation a performance metric for upper-level managers, and the situation will improve within hours.
replyMSFT has same policy. Office365 does not treat Microsoft.com emails any differently. Only exception is Office365 transactional emails.
replyThis seems logical, you don’t want your service to get a bad rep because some internal division marketing team goes dumb. Also, security in case individuals get hacked.