Depending on how many people have a place with a power outlet (ok, a garage) in close proximity to their car and depending on how many people frequently drive less than their range per day (and less than their maybe underpowered power outlet can charge in one night) that might save on quite some public outlets. But I don’t know the numbers.
I know many people where this would apply, though. And those outlets are included in this number, anyway. Which kinda supports my assumption: I think you might be able to get away with actually many fewer public power outlets than gas stations.
edit: There's a culture difference with regards to driving that I explained in another comment just now. Reading some of the other comments further down makes me think that very few people commenting here understand the laws and culture behind driving in Japan.
In the US and Europe having your own, dedicated place to put your car is probably more or less weakly coordinated with owning a car (maybe less in the US, where at least in some places owning a car is more of a requirement?). Just because being able to afford a car is probably weakly coordinated with being able to afford your own spot. But this regulation should make that even more so in Japan.
Every Nissan dealership has a charger, and I've never seen any queue for it, but it's almost always occupied.
For some commenters the article (or its headline) serves the sole purpose of self-adulation: Keeping your bias working. Adding 'stats' to back your argument. Something to numb other peoples criticism in a discussion.
In that sense, any subleties of Japanese culture would actually hurt.
The majority of e-car owners would be comfortable to charge the car at the company parking lot (for cheap), and then even allow the grid to unload some power in case of spikes, when they can offer good incentives, like promises to keep them at 95% at the end of the workday and monetary incentives for taking out power when needed in the city.
The big problem are still expensive spikes, and with all those batteries it would be much cheaper to handle them. The best strategy is to arrange that with the parking lots of the big companies.
Even worse in the USA where you have 110v in homes rather than 240 V which is common in Europe.