But when you have dozens of databases, each owned by a different company, and they feed off each other perhaps once a day, then you can end up with a long time before all your data is deleted.
And that’s their problem, not mine. If they structure their email campaigns such that it takes a long time to update every database, that’s a design choice on their side. When that design choice means they effectively ignore my unsubscribe, well, I don’t see why that should receive any sympathy.