I still don't understand your point. For your argument to be valid, you'd have to assert that a factory can build new mail trucks faster than you could add charging points.
There will be one factory pumping out cars on a specialised, serial production line. It will be competing with 30 thousand locations operating in parallel.
LLVs are past their expiration date everywhere and likely need replaced all over the country. But, it doesn’t make sense to add charging capability ad hoc for a single parking space in a lot when a new vehicle is sent out - the marginal cost of each space is not linear — you’d retrofit an entire parking lot at one time.
If 10 locations have 10 existing vehicles each, and all of them need to replace one failing LLV, going 100% electric for new vehicles means you need 10 vehicles but a retrofit for 100 parking spaces. It does not make sense to tear up a parking lot every year for one new vehicle over the next 10 years.
You wouldn’t replace mail trucks individually, you would fully transition each location as a unit.
Also, you overestimate the complexity of installing charging points. In many cases the parking will be directly against the post office building. In many cases you would only have to dig a small trench. In some cases you would string up a new overhead wire. When you’re doing 10 at a time, this isn’t complicated or expensive on a per vehicle basis.
There will be one factory pumping out cars on a specialised, serial production line. It will be competing with 30 thousand locations operating in parallel.