BMW is making 2x as much licensing the i3 drivetrain as they did on their vehicles. It is expensive to license. The licensing alone is paying for their entire electric division. They only sold 311k cars last year, so a postal contract for 200k/yr would put them in a position, where they can’t produce enough of the engines.
It might not qualify for European or California incentives. or possibly fedex/ups was willing to pay a premium for all electric.
It depends on the drivetrain, and demand. I think the F150 drivetrain, will be about the same one used in their explorers and police vehicles, and possibly the mustang and expedition. They have to design it in those vehicles, then it has to be able to be installed on the assembly or else the costs go way up. They had to wait for new generation builds to do that. Retrofitting is expensive and you typically don’t get the same quality, which gives it a bad reputation, which they are trying to avoid.
I am guessing say Ford has something designed for the 250 series. There will most likely be an initial surge in sales for the smaller vehicles, and once that backs off and they can catch up to demand, and fix any flaws found in the field, they can release other models. Most people use 250s for commercial purposes, so they want those as flawless as possible. The people that beat their trucks up the most are the F150 folks in part because of sheer number, but also because of the tendency to use a 1/2t for things they really should have a 1t for instead of converting their 1/2 ton into temporary low-rider.