Repair-It

You appear to have done some Tesla math there and failed to account for the electricity required....

So here's my math. $550/yr amortized replacement battery pack cost (probably less). Assume electricity rate of $0.15/kWh. Normalize to a daily average route length of 17 miles per truck. Assume a modern gas only fuel economy of 15 mpg, or a gas-hybrid (non-plugin) fuel economy of 30 mpg. Assume a gas price of $3/gal. Assume electric efficiency of 45 MPGe (really a swag). Which is about 75kWh/100 miles.

5,300 miles per year for the truck.

Gas truck operating cost: $1,060
Gas hybrid operating cost: $530
EV operating cost: $600

Sensitivity analysis wise, the variables are pretty important to nail down in this scenario. I gave the gas hybrid twice the economy of gas only just due to the ideal conditions for a hybrid. We could add a small diesel option and say it could manage 25mpg, and that average diesel cost is $3.75.

Diesel truck operating cost: $795

10 year operating costs
Gas: $10,060 + maintenance (oil changes, other servicing, repairs)
Hybrid: $5,300 + maintenance (same)
EV: $6,000 + maintenance ($5500 battery replacement, servicing, repairs)
Diesel: $7,950 + maintenance (oil changes, other servicing, repairs)

We can normalize out the other, non-powertrain related repairs, though you'd save on brakes in the hybrid and EV option. Oil changes also aren't that expensive. Probably 1 a year is all they need in modern times.

So if the EV was $4000 more at initial procurement than the gas, it would break even in 10 years, just from an operational cost standpoint. But gas stuff needs more maintenance. And the EV will need a new battery. It gets complicated. Do you think the non-EV vehicles will need $5500 more in maintenance over 10 years than the EV? Maybe. At which point that is also a wash.

From my initial analysis, I'm not sure the EV is the clear-cut winner.

You forget the PR value of having EV mail trucks, and the potential for various discounts/extra funding that could probably be wrung from the larger government to fund this type of initiative. Depending on who is in charge at the time, of course.

I suspect that EV is not the best value, mostly because I'm certain that UPS is closely monitoring every aspect of delivery and hasn't switched to EV's yet. Their situation is a bit different (bigger trucks) though.