I've got a hills-sachs in one shoulder and a reverse hills-sachs in the other (posterior dislocation). My understanding is that you didn't just acquire that from wear and tear, you dislocated it some time after 2020. The lesion (divot) occurs when the humerous chips itself against some other shoulder bone as it tries to go back into the socket. I'm not a medical professional so you should check this.
I'm just a patient extrapolating info from my health professions, so you need to check what I am about to say with your health professionals. So with a chunk missing from the ball of the humerous its going to be more prone to shifting out of perfect alignment with the socket and aquire wear. So the thing to do is to strengthen the rotator cuff muscles so that they exert plenty of pressure keeping the shoulder sitting properly in the socket. You would have been prescribed plenty of these I assume?
I'm doing rotator cuff exercises almost daily, I plan to continue indefinitely, its not some short term rehab thing for someone in my condition. I've also been taught how to move my shoulder "properly" to minimise it being pulled unevenly and to reduce the chances of the supraspinatus wearing out. Rounded shoulders and not lifting up the lateral end of my collarbone in the direction of my ear when overhead lifting (or paddling) constricts the narrow space in which the supraspinatus passes and its more likely to wear out. So I don't just paddle without thinking anymore - I can't be constantly monitoring my motions, but I always start a session paddling out with concentration and give myself periodic reminders. I've also been taught some shoulder blade flattening exercises - its too hard to concentrate on shoulder blade movement when I'm surfing along with everything else, but the hope is making it a habit on dry land will carry on subconsciously in the sea.
Paddling to exhaustion is also likely to lead to a situation where the muscles aren't working in perfect balance. So I limit sessions to about 1hr and take a rest day every couple of days.
I think you are taking a pessimistic attitude with your doomed statement. We are all mortal and therefore doomed. The trick is not to let one part wear get ruined much more quickly than all the other bits, while having as much risky fun as possible. I'm trying to manage risk now and the with extra attention to my damaged bits I'm hoping to keep it going as long as the good bits are still operating. The plus side is that my posture has had a further improvement from all these shoulder exercises. I'm also putting a lot of work into keeping my core strong. With a solid core I'm less likely to make silly mistakes when trying to do things such as a late takeoff. That's my reasoning anyway. I've got to look after my dodgy back anyway! its come good, but I don't take back health for granted. Of course its easy for me to say this because I'm currently able to surf a lot. If I was dry docked from some injury then I wouldn't be so optimistic. However, sounds like you aren't currently getting much trouble either.
So have you been told you are heading for a shoulder replacement, or just fearing the worst? What do you do to manage you labrum tear? As far as I know I don't have one, but I'm interested.