Interesting post. While there is a lot of truth to what you say, I would offer that JO development and mentorship need to be disentangled. Somewhere along the way the idea of mentorship became conflated with being responsible for your junior officers and their development. In my opinion, they aren't the same thing. There is a minimum standard of support/development of subordinates which should be maintained by everyone in the JO's leadership chain (DH, XO, CO). This is largely what is seen in the wardrooms of ships, subs, etc, and should not be confused with mentorship. I believe the responsibility for developing JOs gradually was abdicated in favor of the idea that the JO's mentor would handle the task. However, a mentor, while certainly helpful to the JO, should be focused on guiding the JO to and through the best choices for that individual based on his/her goals. The leadership chain should be focused on getting into and out of that JO the maximum amount of knowledge and effort possible. You can't assign or force a mentoring relationship, they have to develop naturally or not at all. We are not missing the concept of mentorship or officers capable of being mentors. Instead, we are hurting in the JO development area, as are a couple other communities. You correctly articulated a couple specific areas in which we struggle - regular contact, trust building, and common interests. It is up to the Commanders, the Executive Officers, and other leaders to figure out ways to overcome these obstacles to developing future leaders. I have been in two billets where that was done, in two billets where it was not attempted, and in one billet where it was attempted but results were anemic.
While it has been and continues to be a problem in certain places (particularly in the larger, O-6 commands), I am very hopeful 3-4 years will bring COs/XOs who prioritize developing subordinates as a means of achieving mission rather than satisfying requirements. Our commands have a ton of latitude and maneuvering space, relative to commands of other communities, to implement positive initiatives and cause JOs (to want) to serve because they like it, not just because they can do A or get B, etc. In the interim, all JOs should be very demanding, insistent, and respectful about their own professional development, particularly if they feel it is lacking. It is important to keep in mind your professional and personal development are what is best for your command, yourself and the Navy. Thus, it should be a priority for the JO, and the leadership.