How could physiotherapy cure cervical spondylosis?

It does not cure: it, it is however one of the conservative management treatments that help get one asymptomatic when cervical spondylosis becomes symptomatic. By stabilizing the muscles of the neck minimzes stresses across your neck joints, and help stabilize the joints. Stress across spondylotic joints can induce inflammation and then pain. Remember everyone will spondylosis, it is like having skin wrinkles.