Another plausible explanation was that he was an old man who was basically an academic theologian, which is not a particularly useful skillset for running a major institution in a time of crisis. He acted in what he saw as the best interest of the church.
What crisis, other than self-imposed crisis?
All Popes are old. A strong philosophical underpinning, what you call 'academic', is a great strength, not a weakness. Benedict was and is a strong man. He saw deep evil in the Church that he ran. He quit in response. That is not "in the best interests of the Church".
I cannot help but reach the conclusion that, putting it very charitably, Benedict saw the evil within him, at risk of being exposed, to have fatally compromised his ability to carry out his mission.