>Just taking an existing fast charger with 150- or 350-kW capacity and swapping in the latest and greatest 1,500-kW chargers wouldn’t get anyone faster speeds. The system would need all new “pipes”—grid capacity—to actually move that much current.

The grid doesn't necessarily mean "pipes" or power lines. You don't build a pipeline to every gas station. Mobile charging robots work pretty well in China.

Also I guess they could put a large battery at the charging station so it can take say a steady 200kw from the grid and be able to kick out 1500kw for ten minutes occasionally. That could also charge from cheap off peak electricity.