There are loopholes that allow incandescent bulbs to be sold in the US still. However, replacing incandescent bulbs would do basically nothing to help with this

There are loopholes that allow incandescent bulbs to be sold in the US still. However, replacing incandescent bulbs would do basically nothing to help with this kind of power shortage caused by a cold spell - all their waste energy is heat, and they're as efficient at producing it as any other resistive heater. Switching to LED lighting saves people money during more normal times but makes the long-termp peak to average power usage ratio worse, and ordinary people have no reason to care about that because they pay the same amount for power during this kind of peak than they do at any other time even though it's a lot more expensive to produce.