I have also converted mine, about quite a long time ago. I only had understood the convertible note concept behind SBD but I didn't know how huge the debt was until I read your post.
To make apparent the importance of converting from SBD to STEEM, maybe we can try to have like a challenge or advocacy lead by some of the most influential people here in Steemit - since it's a social network, maybe it will work.
Great idea!