I'm sure companies would love to speed up the time from project announcement to delivery as much as us, maybe more, as they make money faster and I am not too cool on spending it faster.
They usually pick a prototype they think will sell well, has multiple options for road names (Scale Trains and UP turbines aside. And don't ask about the rash of Big Boys.), and can be run multiple times.
Not sure an SD45-2 meets those criteria, and it was a longer frame than the SD-40-2, so you can't just plop one on a Kato.