Look up the cities and counties that have 20-80 electric bus fleets just sitting. Can't get parts, companies went under and no support, etc. 

There are real-world cases all over the US and beyond where the electric only bus is as good as a paper weight. 

Speaking of diesel....the local school here got a few gas powered for their last new ones. Less starting issues in cold, no emissions to go wrong down the road, no cold fuel issues.