Look, I don't know where this idea came from that electricity is this hard problem. It's not. As it is now, many of these LLVs have to be fueled sometimes multiple times per week. Simply plugging into an external outlet not only is cheap but will actually save time.
People who do not have electric cars keep looking for an inventing some kind of "gotcha," but they really are this easy. You literally can just use a normal external outlet to charge them, and even if you want faster charging (totally unnecessary and probably undesirable for this application), it costs maybe $1200 to get an RV hookup (equivalent to L2). I charge from an old dryer outlet, although sometimes use an exterior 120V. It really is that easy. In fact, I don't know if big USPS locations have refueling depots like bus depots do, but if they went electric, they'd be unnecessary and could be removed.
https://www.nytimes.com/2020/04/16/business/electric-cars-ci...
You are entirely correct that the concept of an electrical outlet is not difficult. Commercial real estate is a bit harder, however.
Bear in mind that this contract is for a company to build trucks, and what you describe would be work that is out of scope anyway. The current fleet is way past its replacement date, and needed to be replaced about 10 years ago already. The USPS has funding issues at the moment and it is entirely possible that they cannot afford to do everything at once.
While you claim that it is "1% of the vehicle cost", I think some quick math would indicate that there's no way this is right. 4.8 million dollars to retrofit 40,000 locations for EV charging? That's $120 per station. You won't even be able to pull a work permit for $120.
And while 1% is too optimistic, you'd presumably install multiple outlets at a time.
But that's an expected expenditure over 10 years, and you have to have the ability to charge before you can use the vehicles. That's probably another important factor, because LLVs are past their expiration date now. You're right that it makes sense to upgrade an entire facility's electricals at once. That's almost certainly what will happen over the course of the rollout, but the need for replacing LLVs is likely evenly distributed among locations.
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.
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.