I think it's more misleading to claim that any written standard has authority. In practice these written standards are ultimately subservient to the actual impl

I think it's more misleading to claim that any written standard has authority. In practice these written standards are ultimately subservient to the actual implementations—particularly where the competing implementations happen to agree. And especially in disputes that affect real websites. If there is an inconsistency between what the standards say and what the browsers have done, the browsers will more than likely trump the standards. In all practical senses the standards are descriptive, not prescriptive.