That's not 100% right. It's currently free for non-commercial purposes (and will remain so), but we still have to develop our strategy for people who want to sell mods or even full games. We didn't look at it yet because it hasn't become a thing yet, but we'll come up with something that's fair for us and those who want to commercialise.
Follow the D&D 3.5 model and let everyone do everything for free. It made those guys a fortune and it's why people are still obsessed with D&D 3.5. It will make you guys the industry standard for this particular niche of gaming because every product everyone else makes will be an advertisement for *you*.
It sounds crazy but with the internet? It works.