It’s free only if you are a hobbyist, not when you produce a game with it (with the rightful and well deserved percentage to Epic).
Yes the staff at Epic are probably stretched thin, If only they stopped trying to please everybody with the engine and less VR editing features as well : ). But as someone pointed out lots of the dynamic light and shadow issues/performance need fixing first before any GI implementations.
On a sidenote: While some devs have all the right to ask for GI implementations, I would say that by having GI in the level doesn’t necessarily or magically make a scene look better, you can achieve good results without GI if lighting is setup correctly. Some examples like Horizon Zero Dawn or even The Witcher in some instances come to mind. Open world games are already a huge production (unless you are creating something very very simplistic or stylised) which is why you probably don’t see large studios using UE4 complaining here, because if they can afford to do open world games they will afford to build their own GI for it if they need to and wouldn’t bother waiting for Epic. The rest of us here who need good GI are at Epic’s mercy.
I am more interested to see a GI/indirect lighting hybrid that would work well for moving objects characters/faces, i think it is still very tough to get good looking character under just skylighting without direct contribution from a light source especially to have sss react to it and reflective areas to work under proper shading.