Because we have offshored most of our heavy industry. For national security reasons we now have to re-industrialize. Plus a lot of the infrastructure for transportation and heating is gradually shifting off of fossil fuels. So electricity usage is going to go steadily upward for the next couple decades. This would be necessary even without AI data centers.
I think we reached peak "electricity" for the consumer decades ago. You know...when our TVs were a giant electron gun pointed as a phosphor screen whilst the room was lit with a filament of 3000 degree tungsten.
...and Americans were getting like 200HP out of a whole ass 7.whatever L v8 ahaha.