Your excerpts don't divulge whether one of the bus manufacturers is required by law to pay health insurance, social security, and other labor costs. Are they required by law to treat the water from their cooling towers before they dump it in the river? Do they have to pay a 50% tariff on imported parts?

I'm sure there is a lot of slop in different purchasing departments. They can probably all tighten things up. But there are legitimate reasons for one product to cost more than its twin. The U.S. should not allow twin products to be sold on the same shelf if one was not manufactured under the same rules as the domestic product. If all three of these products played under the same rules, then we can point fingers. Without that you are just ridiculing the company who knowingly takes a hit for purchasing from responsible vendors. If that is what you are doing, shame on you.