At the beginning and at the end, the author mentions deliverability to major providers such as Google as the core outcome, but in between they don't substantively touch upon it. It seems unlikely that the goal was accomplished in a durable and intentional way.
Deliverability is my only remaining issue, even after years being hosted on Vultr and doing “all the correct things” and staying off any and all blacklists. I frequently have eMails never reach their recipients because their providers just silently drop the incoming eMail. It doesn’t even show up in their junk folder.
"In order to deliver email to other mail providers without being marked as spam, I ideally needed to implement all three policy frameworks with the mail server."
Then a few lines later:
"Inbound and outbound message delivery was working."
