I think one of the hard things about operating any server is securing it.
If the author is arguing that 'mail is easy now' you can't make that argument without addressing the security aspect. I hate google and I still use gmail because their project zero team is so good.
Big consumer tech companies are finding their own ways to make this argument: apple with privacy, google with security research, even facebook with providing better privacy controls, although this isn't in their DNA and they'll fail. More products are supporting MFA/FIDO now.
If 'mail in a box' etc are going to convince me to self host (which I would love to do), security is the missing piece.
