It is commonly held that bishops "must" offer their resignations to the Roman Pontiff at the age of 75. I think this assumption (for that is what it is) needs to be reconsidered.
A starting-point must be found in the sacramental structure of the Church. We must discard the idea, which has, I think, grown during this pontificate, that a bishop is a district manager in a multinational corporation and is liable to dismissal. He is not. He is a Successor of the Apostles and the charismatic High Priest and sacramental organ of his local, that is, particular, Church. The only exemplifications of the Church Militant by divine institution are the Universal Church, gathered round Peter, and the particular Church gathered round her Bishop. Everything else is merely organisational and, in principle, transient.
It is to the credit of those who wrote the current Code of Canon Law that they understood this, at least to the extent of not making episcopal resignation automatic. Only a bishop can truly be the judge in this matter. I would only countenance a different approach in contexts of major ecclesiastical crisis, in which a primatial intervention may be necessary. The Arian crisis; the case of episcopal traditores after persecutions; the reforms of S Gregory VII; might be examples of this.
But the authors of the 1983 CIC in fact went further in their reticence than this. They did not make it mandatory for a bishop to resign, at 75 or at any othrr age. In Canon 401 para 1 (which has no antecedent in the 1917 Code) they said that a bishop is "asked" to offer his resignation. "Rogatur".
And there is more!
Para 2 says that a bishop who, through illness or another grave cause, has become 'minus aptus' to the exercise of his 'officium',"enixe rogatur" to offer his resignation. "enixe" means something like 'strenuously'. But in the previous paragraph, where the age of 75 appears, the adverb enixe is absent. In other words, the 'request' that a bishop offer his resignation at 75 is not as strongly urged as the advice offered to very sick bishops.
If enixe, semantically, has any meaning, then the absence of the word must also have meaning. If enixe strengthens, then its absence weakens.
I would like to see an understanding that, whatever advice is politely given in Canon Law, the Apostolic status of a bishop and his own personal responsibility before God for the decision he makes, are not taken away.