Yup, transistors especially have given us major breakthroughs in the ability to step up/step down DC. Also, there have been huge breakthroughs in High-Voltage

Yup, transistors especially have given us major breakthroughs in the ability to step up/step down DC. Also, there have been huge breakthroughs in High-Voltage DC: https://en.wikipedia.org/wiki/High-voltage_direct_current https://en.wikipedia.org/wiki/High-voltage_direct_current At certain huge (grid) scales they have found that AC and DC swap "efficiencies" again and we're increasingly starting to see current flows as DC-AC-DC "sandwiches" with DC used by the majority of consumer electronics and DC used for extremely high scale grid transport, and AC still useful in the mid-range transport.