Even if the power load on the grid was doable, heat dissipation is also a huge problem. Current DC fast chargers max out at 350 kW (in theory, my car supports charging at that rate but the best I've seen in real life is around 190kW), and the liquid-cooled cables are already heavy/bulky enough to give some women and older folks a hard time. I can't imagine a practical way to handle 2 or 3 times the current without making the cables something like 6 inches in diameter and weighing a couple hundred pounds.