It’s not like almost every single game is open world exploration game nowadays. Yes, out of the box support for Time of Day mechanism would be really nice, but IMHO it’s easy to script it too. Did it for one game and it didn’t feel like missing anything.
Of course yeah… different game, different needs. But that’s probably not right topic to discuss it 
Yes, it’s totally limiting. I hate it as designer. Still… there a lot of games need it. VR and mobile games need lightmaps to achieve proper framerate.
Even open world games use it. Assasin’s Creed series doesn’t use dynamic Time of Day, they’re baking few lightning states representing noon, evening, night, etc + smart use of dynamics.
The atmospheric game like The Vanishing of Ethan Carter, that I was working on, had to use prebaked lights. Not only because of the perfomance, artists relied on soft “eerie” looks of static lightning to create specific mood of the game. Sold around 500K copies on Steam alone in the first year. I bet there are a lot more successful titles using baked lightning out there
That being said… we’re still far from efficient GI in UE4. There’s a lot issues and features waiting for ages. I agree on that, but I do accept harsh truth: this engine needs to satisfy needs of very different games. Like one of Bioware’s developers said “Frostbite is like Formula 1. UE4 is like SUV, a car for entire family”.