[DangitBobby]

> IP range reputation is not easy to assess, sometimes even for email professionals.

The article is about a man who has been sending emails from the same address for the last couple of decades, and it has always been in his control. Is it difficult to assess the reputation of his address? You seem to be deflecting some blame onto the victim of the shortcomings of your system.

[massaman_yams]

This is not my system, to be clear, but you might be surprised how little 20 years of data matters to filter accuracy, empirically speaking; recent sending behavior carries orders of magnitude more weight.