Comment by __jem

Reclaiming the physical storage of an unused column is often a costly and sometimes impossible operation, which is why many legacy applications end up with the equivalent of my_column_final_final_v2. Database administration requires compromises like this sometimes in the name of uptime and data integrity. Big migrations are always inherently a little risky, and from the view of many DBAs, why even risk it just for a bit of clean up? Your schema shouldn't be totally transparent to your application's business logic anyway, so there are better places to enforce naming hygiene.