A 5kW unit, if installed everywhere might also not be feasible because the conductors burried in the ground are not thick enough to carry 5kW times all the cars in all the houses on a street. That means they will need to remotly regulate charging power/when stuff charges OR every street needs new electrical infrastructure which isn't the cheapest option.
Depends on the diversity/simultanity factor used in the planning. I am not sure if this is the same everywhere, but typically the copper in the ground is not calculated to 100% load of all attached houses and the farther you get away from the house the lower that number will get for economic reasons.
