I think we've all been there, you've been asked to write something to send bulk emails for whatever reason. It's a solved problem, theres a multitude of companies out there to handle this for you, and theres no point in catching up on their many years of single minded focus on making sure your email reaches its destination without being waylaid by spam filters.
Now, I could go into a point by point talk about DKIM, SPF, ISP rate limits, content inspection, bounces, getting blacklisted, getting unblacklisted etc, but the eyes will glaze over.
How do you convince a non technical manager of the issues around bulk email like this?