Worth a read.
https://www.fresnobee.com/news/politics-government/national-politics/article258818708.html#storylink=mainstage_card
That gives some great context and background. It puts it in a very different light knowing that the RFPs went out in 2015.
It does beg the question of why it takes 7 years to procure a mail truck.
It ends up being the opposite of procuring a new fighter jet. In that case, it takes a long time because the final product will be at the limits of engineering and that's complex and the details are so hard that, as we've seen, sometimes the process fails altogether. In this case, it will be loaded with decade-old engineering while the "civilian" fleet will be acquiring actual new tech.