I don’t think there’s anything inherently wrong with them not focusing on it, especially with the other things they’ve been doing - such as mobile improvements, which I’d argue benefits a larger proportion of it’s users. We all know by now that Epic focuses on things based on it’s games first, and currently that game is Fortnite.
I suspect that DFGI started out as an experiment to see whether it would be viable or useful for Fortnite, but was canned when they realised they didn’t need it. Purely speculation but quite likely.
I understand the frustration for sure, but outside of the financial aspect there’s no reason someone can’t hire a rendering engineer to implement a solution that works for their game. For now at least that’s what it’s going to take if things like VXGI and LPV etc. won’t cut it.