There are 160,000 miles of highways in the US
And 3.5 million square miles in the continental US.
To have one charging station every 25 miles of highway would only require 6400. Freeways have a lot of crossing points and interfaces, putting the charging stations near those would greatly reduce the number needed.
To have one every 25 mile square ( 625 square miles ) over the whole country would only require 5600, so clearly 6400 to cover all the freeways is more than is needed.
There are approximately 120,000 gas stations in the US, that’s one every 30 square miles. ( Obviously they are not evenly distributed. )
Having that many means that you can drive in any direction from just about anywhere ( that isn’t the middle of the Nevada desert ) and run into a gas station within a few miles.
Why do we have so many gas stations? Clearly we wouldn’t have that many if they didn’t make money ( even at the thin margins they sometimes have ). There is a lot of gas pumped and a huge market to capture, so gas stations spring up at a far greater density than is necessary to capture all that money. There is a limit on how much gasoline that can be stored in the underground tanks, and how fast the tanker trucks can refill them that will set a lower bound on the number of gas stations. Electric charge points don’t have that problem, but they will run into a limit on space for the cars to park while they charge…. which is why they need to go into existing parking lots and not into any new space.
It’s all just a question of how fast we convert existing parking spaces into parking spaces with plugs.
The age of the internet means we don’t need them everywhere for you to randomly run into, your car could find them for you, it could always know which ones are along your route and suggest appropriate ones.
Even without that – having 10% as many charging stations as gas stations could cover the entire country so that an EV with a 25 mile range could get you from anywhere to anywhere.
An EV driver wont need to charge for daily errands, only when going on a long trip, because your home is always a charging station for you, so you can leave with a full charge.
If you are driving to a friends home, that can also be a charging station for you, to top up for the return trip home. If you are driving on a trip long enough to need a midpoint recharge, a friends home on the route would also be a viable option. Why not stop in and see friends?