Earlier quoted context omitted.
I think the gist of the article is that we don't have the same busses across the US. Yes there are only two major manufacturers, but they're all being procured in different ways, in different custom configurations, all across the country.
We do. What is different is the options. The bus itself is the same, but you can put options on the bus that drive up the price.
if you end up buying a whole bunch of units of the same stuff without planning to, you're wasting all that potential efficiency.