Warning. A view from the "other" side.
It does seem to be an unfortunate fact, but isolating the reason for post-prostatectomy incontinence is quite difficult. Once the integrity of the urinary system is upset, it can seem like pot luck whether continence is preserved (the odds of dryness are good but that does not help the men who are on the "wet" side). Clear medical causes like over-active bladders, strictures and urinary infections can be attacked, but if there is no clear cause, the evidence for solutions seem to be less well defined.
PFEs (Kegels) usually are the first stop and have been my particular bète noir; if I had a £1 for each time I have been told that they are the answer, I would not be rich, but the cost of my artificial sphincter implant would have been offset very slightly. I was still being given the Kegel message, even after a physio admitted that my pelvic floor was like a Bulldog Clip. If Kegels are being done, and continence is regained, then it is assumed that they are the reason without looking at other factors, for example, would continence have been regained by that point anyway? It is impossible to say.
In my mind, the issue is that having looked at and tried the various "solutions" (in inverted commas because some are heading for snake oil), the biggest hurdle is learning to reprogram the brain to stop incontinence from dominating life. After all, cancer has been beaten. Shouldn't we just be glad we are alive and that we are not in the group of men (for whom I have an infinite amount of admiration) who are struggling with HT, RT and similar treatments? For some men, reprogramming the brain may work. For others, unfortunately it doesn't.
The corollary I have cited several times is that messing about with nature (urinary system = nature) is rather like the twin carburettors on my Triumph Dolomite. For several years of ownership, they worked perfectly. However, after the jets were replaced, the carburettors had to be retuned and rebalanced once every two months or so. Even expert mechanics could not restore the previous level of reliability.
If I could postulate an approach, based on my experience, it would be to try all the reasonable remedies first (i.e. avoiding snake oil, and there is a lot of it out there). If the remedies don't work, try the mechanisms for coping with and managing incontinence to find those that match your lifestyle, and at the same time, work on your brain (with help if necessary) to reduce the size of the elephant in the room so you can concentrate on more important things.
Hope something here helps.