Gday, For what it's worth, I got this response from the Thai Embassy Canberra regarding the health insurance requirements. New applicants only from their advice.
TLDR : Answer Summary
A user shares information received from the Thai Embassy in Canberra regarding health insurance requirements for new visa applicants. Other commenters discuss their decision to obtain insurance regardless of official guidance to avoid issues upon arrival, and note the inconsistency in updates from various Thai consulates.