Voltage drop is a calculation. It doesn't massacre Kirchoff in the process.
AC conductor calculations ARE BASED ON meaning CALCULATED ON the fact that series conductors are utilized. Ya know series? Two wires in parallel. One going and one coming.
Maybe alternating current tickles electrons to the point where they start giggling and forget what they're doing.
AREA UNDER CURVE of the sine wave determines energy value in the transaction.
Ever experience a single cylinder Norton 750 cc motorcycle?
POM POM POM POM POM
A 750 anything else would run circles around the Norton.
Look at it this way. You need to do research and find out the VALUE of efficiency of three phase versus single phase. Or 400 Hz military power versus 60 Hz. Or even DC over AC for motor sizes. An itty-bitty gear reduction starter motor may be 3 hp and three times the size of an AC motor. And no, the addition of heat sinking will not make the two comparable.