The purchasers for buses, trainsets, etc., are bad- lots of unnecessary customization, last minute changes, low volume, etc. This drives down efficiency across the system.
RE volume, a couple of years back, Ireland, a country of a little over 5 million people, recently made an order for 800 electric buses over five years via the national transport authority. Meanwhile, the transport authorities in the article, in a country with 340 million people, made orders for 10 and 17 buses respectively.
Now, I think Ireland's extreme centralisation on this is unusual, but the US's approach of having loads of absolutely tiny transport authorities is, too.