I find this whole premise to be flawed. Are you aware that the foundation was allowed to look at unreal engine’s source code while they were developing eevee? So since epic games was aware eevee was being developed, why didn’t they pull strings in the initial development phase and have the foundation incorporate eevee into blender in such a way that would keep a third party from improving it in exchange for the 1.2 million dollars?
Regardless of what the foundation does with eevee, there’s nothing stopping outside developers from forking it and adding features to it that would make it more of an unreal engine competitor. There’s already an addon from an outside developer that adds SSGI. What stops people like that from adding features directly to eevee? They may even develop a way for eevee to hand off some elements in the scene to cycles and have both renders work to produce the final image in the future, so we can’t even say improvements in cycles won’t impact eevee.
To me this is just another case where someone would rather development focus on just the areas they want. The foundation committing to improve one area doesn’t mean they have anything against the other areas. They can’t improve everything at once and there will always be users who aren’t satisfied with what they do chose to work on.