I hardly ever hear anybody mention the infrastructure itself being in need of upgrade.
Wires can carry only so much current before they become glowing fuses.
There are actual fuses in the system that will blow and save the wiring from melting down.
Wires of a certain size can carry only so much current before it becomes a red hot heating element.
The grid was never designed to carry the amount of current that will be necessary to charge millions of EVs simultaneously.
Ohm’s Law will not be ignored.
Most homes built before 2000 were wired for 100 amp service. That’s 12 kW per home. Newer homes are typically wired for 200 amp service, that’s 24 kW.
Now imagine every home in a 500 unit subdivision all having EVs charging at the same time, regardless of time of day.
Transformers, relays and the wires themselves will all need to be replaced with bigger and more powerful counterparts, else they will be burning out or popping line fuses all night long.
And this will have to happen all across the country.
The power utility companies will naturally have to pass along these upgrade costs to the consumers, even those that do not own an EV.
Utilities that are owned by local governments will have political problems with their electorate screaming for relief.
That is why the transmission lines operate at obscene voltages and transformers are used to step the voltage up and down. AC is used so that the transformers work.
In my case that's a situation of a limit on converting DC power to AC power. But it's an example of capacity limitation similar to the grid. Even if we add more power production (i.e. coal or natural gas or nuclear fueled power plants) there's still very much the issue of increasing the capacity of transmitting the power to homes and businesses. And then increasing each home's electrical system to handle it.
My house was built in 1998 and has 200 Amp service.