I think that exactly the root of the problem here. They wanted to benefit from the enhancements on both sides of the fork, already signed an exclusive agreement

I think that exactly the root of the problem here. They wanted to benefit from the enhancements on both sides of the fork, already signed an exclusive agreement with Cry, but want the fee structure from Amazon. I only mentioned CryEngine being more mature because they have more dedicated resources working on it, and from what I understand dev studios contribute fixes back to the engine as well.