Hello from JA
It is because this is a somewhat separate issue.
This is degenerative disc disease of the spine.
Exact causes are unknown.
But with any wear and tear, the process can be accelerated. Discs dry out...become dessicated.
This lowers the ability of the spine to have support, resulting in arthritis of the spine.
Any injuries, bad posture, etc...makes it worse
Without the correct manual therapies, or with abnormal motion of the body, the disease relentlessly progresses.
Please let me know if you have further questions.
Please don’t forget a positive rating.