It's just that spammers don't have enough money to use bots yet.

There's probably a lot of truth in this!

At the moment, I'm targetting the long-term vote-buying-bot-farming group of accounts. He's a stubborn one and rather than stopping, is doing more so I'm rallying more troops to join the downvotes. If I can get a couple more of the bigger accounts to downvote regularly, it'll be enough to move them from profit into loss. If not, I know that my downvotes along are costing him nearly $10 per day so I'll keep chipping away whilst my power increases and his votes remain the same.

Once this user's done, maybe we'll have time to eat a few of the small fish 🙂