Why? Yes, Epic’s been slow to implement some features, most notably realtime GI and volumetric , even though those are the two most wanted features in the entire engine according to the votes, but Unreal isn’t just a graphics engine. Games have been faking light shafts for decades, in some of the content packs on the launcher available for free, Epic even has one of their attempts to fake it. Is it really worth all the time and effort learning a new engine over it?
For every the CryENGINE does right, with the engine actually having both realtime GI and volumetric right out of the box, there are just as many things that the engine lacks that Unreal does really well. Personally, I would rather use the tool that makes my life easier in other aspects and have the visual come when they’re ready than abandon everything for it. They were out of the backlog for a bit as it is, so someone’s clearly interested in getting it done, it’s just not one of the priorities Epic has as a company right now so it got pushed back temporarily.