For the life of me I don't get the shortsightedness of the "up or out" philosophy paired with the lack of career flexibility. A lot of people become pilots in the Navy because they want to fly, and have no desire to be a DH, let alone an admiral one day. Yet we constantly force folks out of the cockpit, and we refuse to create pathways that allow pilots to reach 20 years of just non-golden path flying billets. In turn, we push fully qualified and very experienced pilots, who have no desire to fly for the airlines but also no desire to be a staff officer, and replace them with nuggets. Instead, these folks could be rotating between instructor/station SAR/GITMO/etc and operational flying billets as Super JO's / FITREP fodder DH's who wear O4. Creating a real PIP that isn't just for show would also help.
I also disagree that all bonuses just go to folks who were going to stay anyway. I am at that juncture myself right now, and my decision to stay or not will absolutely be influenced by the size of the bonus. And my decision to take the 5 year bonus or wait until after the DH results to take the 3 year bonus will also be affected by the size.