I don’t understand why Microsoft are so bad at this?
They have access to a large percentage of all email traffic to train domain reputation, and spam detection models on yet seem to be notorious for both false positives and false negatives.
I think they cannot be bothered. Their customers are more tied in than Google's and are not going to switch because a small proportion of emails are rejected.
More specifically they seem to rely IP reputation rather than domain reputation, and IPs do change hands, especially for smaller servers.
