A third of club churn is just failed credit cards. Another chunk is wine piling up unopened. Both are fixable.
Model: churn 25-30%/yr; card-fail share 20-45% of churn; saved-member value = ARPU × 14mo; 25% of voluntary churn saveable. Benchmark, not audit.
Open CLI: winery_club_churn.py in the repo.