I think range is still a limit for most. I live in the Washington, DC metro area. WMATA (the regional transit provider) runs mostly hybrid diesel and CNG buses. They have found that while CNG is cheaper on a per mile basis just concerning fuel cost, most of the CNG buses can't handle a double shift on one fill of CNG so they end up having a lower percent utilization than a diesel since they have to head back to the garage for a long refill after each driver's shift. Their CNG buses typically fill overnight as they take several hours to fill. A diesel takes minutes to fill, so even with the same range per fill, a diesel can run nearly continuously. Not all the WMATA garages support CNG and plans to build CNG infrastructure at more of their garages have gone slower than originally planned and my understanding is the primary reason is the operational constraints of CNG fueling.
Electric vehicles currently have the same kind of limitations as CNG. Without expensive infrastructure for doing things like en route charging, a bus needs to be able to comfortably run two shifts back to back before a transit authority can use them on a wide scale - probably roughly a 300 mile city range. The charging infrastructure even in a garage is expensive. Swapping enough batteries for a 300 mile bus range is also labor intensive. I agree that electric makes sense here, but the infrastructure just isn't there yet.
Van based trucks (think UPS) are light enough that they're not that hard to electrify from today's standards. However a medium duty truck like a box truck gets roughly the same kind of fuel economy as a transit bus and so the amount of energy you have to carry to make them work well today is still expensive and hard to do.