From what I understand, 5G was first about increased capacity. Increased speed was a secondary point. It optimizes how multiple users can share the same bands, and adds use of higher frequency bands that don't propogate as far. So for very high congestion areas, they can deploy smaller cells and which each can maintain higher speeds per user. I think the "faster" part was just marketing to get users to buy into the new technology. I mean I think that was the intent. Something about the implementation needs tuning though.