There is an MSE post about deletion of questions.
- The system will automatically delete unlocked, unanswered questions that have negative score after 30 days.
I didn't realise this applied to Meta posts, but I suppose there's no reason not to.
Your post was not locked, was at −1 and had no answers. The last comment on it was on March 27, so it was deleted after thirty days or thereabouts on April 25. It's "thereabouts" because deletions are done by a scheduled job.
Perhaps it was too specific for a question. That is, instead of a question "Would this fix this problem?" it seems more common to ask a question "What would fix this problem?" which allows a variety of answers. You could try adding your proposal as an answer to a related question.