I used to play regularly in cover bands three times a week. I had an old fender strap. I had major muscle problems in my shoulder. I switched to a wider strap. The problem disappeared.
Good point raised here for me would be, has anyone ever changed to a wider strap and found no benefit?
In all the posts they mainly relate to the bass in height, as i said earlier this was never a height thread but more a position on the shoulder.
When the focus is on one issue other issues get missed such as "what are the functions of the shoulders".
Now we can all agree that the hanging of a bass from them is not one of them.
So how does this adaptation of hanging a bass affect the shoulders function?
Now myself and others consider the functions of the hands as a line through the arms, shoulders, and to the brain. With that we also accept that any problem in these areas can affect the hands.
Then there is the inclusion on balance, that is the bodies balace not the basses. How does the body stay up-right? Why does it not fall over when the arms are extended in front of it, or we bend or lean over?
Why when we hang additional weight does it not fall over?
If we take that additional weight as a bass, then as a rule we add weight to the top of the body structure, so in effect it is a snap loading of weight, that adds to make the body top heavy.
Again why does the body structure not fall over?
If you move and swing the guitar, it now becomes an ever changing weight in the top of the body structure.
To me strap height is about lessening this effect, more about moving the load from a top heavy position to a one with a lower centre of gravity.
So just on these basic principals, problems like sore shoulders can be helped purely by strap position.
When height is talked about the focus it is usually about the wrists, never about the over all effects on the body.
Many in reality, in protection of their hands with straight wrists, could be causing damage elsewhere, remember that i consider that line from the hand to the brain as all part of the funcion of the hand, as damage along this line can effect the use of the hand. So this extra weight is taken on by the body and a good strap and strap position will lessen its effects by working with the bodies proprioception, so answering the questions posed earlier on the balance issues.
Now as it has been said "its just a strap" but as usual there is more involved if you look outside your focus, and the focus of a strap will tend to be height, because that relates to this focus on wrists, rather than some of the other things i have mentioned.