Thanks for your opinions Alophysio, I've taken a few of your comments to respond to this morning while I have a minute to sit still.

"non-specific low back pain" - what is the common thread?

Protective responses leading to hypomobility of Wikipedia reference-linkfacet joints. This leads to further inflammatory irritations and the cascades towards increased tone and the involvement of more and more of the spine in this response.

"However, the complicated part of MSK treatments is once we have missed the boat. e.g. (in your terms) an L3 referred event leading to quads dysfunction leading to PFPS undiagnosed by either you or me ( ) which leads to Grade III chondral damage/wear. "

Not complicated at all , for the most part the "damage " you refer to is irrelevant . In much the same way as the kinds of degenerative changes seen on x-ray etc in and around spinal joints and adjacenet structures is largely irrelevant. Once normal patterns of recruitment and referred pain and the galaxy of other altered ( referred ) neural events have been turned off , these identified features of the likely interaction of inflammatory chemistry on soft tissues remain , but are rarely the cause of pain. What you are noting are the consequences of dysfunction , rather than cause. A mistake often made by those whose notions of diagnosis are still rooted in the pathology model of MSK diagnosis ( doctors of medicine ).

"Now what? Changing the spinal joints may mitigate the pain temporarily but not necessarily restore normal function to the muscle because it is now inhibited by physical factors and the pain returning."

The purpose and result in dealing with spinal joints is to do what must always be first on the list, restore normal neurology. By doing so it becomes clear , what was local and what was not. In most cases this is all that is required as most MSK conditions not related to trauma ( along with many that are ) are simply referred events . By eliminating these events a lasting restoration to pain free normal function can be achieved in the majority of cases.

"Lastly, if everything were so simple and easy to treat, you should have a massive patient load"

I used to , but I had a year off and now keep a lower profile. There are more things in a balanced life than treating patients . Unfortunately , now that I have returned to private practice , I find the numbers are increasing rapidly again and I have trouble saying no. I don't advertise or accept referrals from doctors, don't see workcover or other compensables. Just cash paying people from all walks of life who manage to hear about me. Many from interstate , some from overseas. My interests vary widely and I do my best to balance them out. There is a lot of joy however , as you would know , in being the person who can fix what others could not.
Cheers