The game has been out less than 11 days. Give it time and such tools will become available.
Also, I don't think people would be allowed to make money from mods. Copyright and plagarism would stop them dead in their tracks. Even if they did have to pay for modding tools, they are still building off of someone elses work (Creative Assembly).
Saying that, if modder were not allowed to make a profit on their work, after HAVING to buy the tools - well, lets just say it would severly reduce the amount of modders and in turn, mods.
Again, such tools you are talking about will become available free over time as more and more people learn the secrets of the games engine/coding. But, if you are willing to buy a program that allows you to make your own version of a game, you may as well buy a source engine and start from scratch. You will have a LOT more creative freedom over the project, and have the opportunity to sell it.