Is that really the case though? Or is it that the games market isn’t ready yet for mainstream dynamic GI, but people refuse to acknowledge it?
Hardware simply isn’t at the level it needs to be yet to deliver this on a widespread level, and therefore it’s not worth focusing on. DGI is still bleeding edge tech, and games which implement it have bespoke solutions that are massively tailored to that project. Unreal has to power hundreds of thousands of projects - but the advantage is that we DO have the source code available so we CAN tailor it.
If folks want to design games around Dynamic GI and/or other bleeding-edge tech, hire a rendering engineer.