We must not limit our boundary of what we regard systems thinking to be, based on one method, i.e. SD. There are more than 10 relevant methods or approaches on ST, and the best definition of this I've seen relates to what is expected of ST practitioners, from an employer perspective. This is built into the Systems Thinking Practitioner L7 standard in the UK, covering not just skills, but also knowledge and behaviours, and anyone can access a copy at: https://www.instituteforapprenticeships.org/apprenticeship-standards/systems-thinking-practitioner/