They are ?
The goal is to remove ISK from the economy.
You can tax money at the production. That’s the same thing as to reduce the income, so if you set to 10% tax it’s the same as to remove 10% of the value of the bounties, blue loot, etc.
This penalizes more the people who arrive later because they can’t have the same value. This does not penalize people with money stocks.
You can tax the money not being used. This however means people are forced to invest to not lose their money. And they also are forced to speculate on prices to ensure the investment does not lose value.
This penalizes people who don’t want to invest. Including, especially, people who earn very little and play very little : if they play ten times less than another player, they are taxed ten times more.
You can on the opposite, tax the money when used. It penalizes the middlemen who must use a lot of money to produce some, including traders and industrialists.
This is the solution CCP chose.
They just need to also tax contracts. And OTC .