Economics has a concept called marginal cost. That doesn't mean "insignificant cost", but instead is the cost of producing one more unit of anything. The cost of making something is the marginal cost plus the fixed cost (development, factory, etc.) divided by the number of items produced. So if the number of items produced is large, the overall cost trends towards the marginal cost. Sell enough of something, and you can sell it for little more than that marginal cost and still make a profit.

That is relevant in the context of game development because the marginal cost of games is very, very low. These days you don't even have the cost for the disc, box, and manual any more if you sell the game online. If you sell enough copies of a game, you can sell it very, very cheap and still not make a loss. Especially if the development was quick and not costly. There have been recent stories of successful mobile games spawning multiple clones within a day. If somebody can see a game, program a clone within a day and put it on the app store, he can make money if he sells that game for under $1.

Game developers tend to be creative types with no clue of economics (or project management, unfortunately). So developer Caspian "Cas" Prince from Puppy Games wrote a long rant on their site in which he complained how Steam and Humble Bundle ruined the prices of games, and that individual customers are now "worthless" to an indie game company. Which if he had studied a bit of economics wouldn't have come as a surprise to him. Development costs of an indie game aren't huge, so if we move indie games from being niche and selling a handful of copies to being nearly mass market and selling thousands of copies on Steam or per Humble Bundle, the drop in prices is inevitable. Sorry to burst anyone's bubble, but even indie games are often very derivative, so if you can make the hundredth 8-bit graphics rogue-like dungeon crawler, so can anybody else. You can't sell such a game for much money, because there isn't much of a barrier of entry to other people making a very similar game and selling it closer to the marginal cost.

So if Cas states that single customers are now "worthless" and flips a bird at anyone threatening to never buy a game from him again, he is right. It is the same concept that Damion Schubert explains in relation to the history of Ultima Online: "His [Gordon Walton] contribution was simple: he was able to convince every level of the organization that change was necessary – and possible. He did so with the single most succinct definition of a griefer I’ve ever heard: A griefer is someone who, through his social actions, costs you more money than he gives you. Well, when you say it like that, we all felt pretty stupid for letting these jackasses hang around for so long.".

Even in a MMORPG at $15 per month it is easy enough for a jackass to drive away more than $15 worth of customers per month. In a game like League of Legends, with an average revenue per user of just over $1, any single player is worth so little, that you can easily afford to ban as many as necessary to keep the game pleasant to everybody else. With many more players in the game the effect of a griefer can still be large, while the money he brings is insignificant. One of the consequences of that is that the worst people have congregated at certain independent forums and sites. Because game companies can't afford these people on the official forums any more and wielding a hefty ban-hammer.

In all the recent discussion about horrible video gamers, this is maybe the light at the end of the tunnel. More and more companies involved with games will realize the economic cost of jerks and step up. Not because it is the right thing to do, but because it is too expensive not to. In a world where there are many more gamers and prices trend towards the marginal cost of production, each individual player is practically worthless and can be banned or treated sternly enough to make him leave without that costing more than the damage he caused by being a jerk.