This is not a manner of a elementry school, It does not matter if it is "fair" to mine bitcoins, And receive so very many dollars from it. What matters is this limit is idiotic. There is no need for it, And it will cause the eventual demise of bitcoins, For bitcoins will become as any other currency. I must buy bitcoins in order to receive them in place of mining them, And this will discourage many. If this occurs, Bitcoins will become somewhat a stock market, You can buy bitcoins when the value drops, And sell them when it increases, Yet you cannot add to this by mining bitcoins, Thus the use decreases, And the value.