A Gallon of gasoline is estimated to have 33.41 KwH! (A normal gas engine throws a good portion of that energy away as heat.) That gallon of gas is pretty close to what my typical household uses in the entire day for electricity! So to pull down the equivalent of a couple of gallons of gas in 20 minutes is going to take the equivalent power drain of a sub-station transformer.
That's some very bald-faced lying.
You already said that the theoretical energy of a tank of gasoline is mostly wasted, but then you go on to use that same number anyhow, as if EVs must waste just as much energy, for some reason. In fact electric motors and Li-Ion batteries are very efficient, while gasoline engines are very inefficient, so the numbers.
In fact a Tesla Model S battery ranges from 60-100 kWh depending on how much you spend, so your gas tank is only 2-3 gallons of theoretical gasoline, while still transporting you 300 miles.
A 60kWh charge in 20 minutes would be no problem for businesses. It's only 375A@480V (3-phase). Here's what 1200 amp, 3-phase electrical service looks like:
Does that look like a "sub-station transformer" to you?
A typical house doesn't use a 480 volt industrial power feed. You don't want much more current in the hands of consumers.
Why in the world would you need 20 minute charging AT HOME? What kind of emergency would necessitate that? Two people sharing a car, both commuting 100+ miles to work, on different shifts?
Most everyone else plugs-in their car, then GOES TO SLEEP. Who cares whether it charges in 10 minutes, or 10 hours, AT HOME?