True, although buses are going hybrid/electric, for instance in my town electric buses started on one line over a year ago:

https://www.hsl.fi/en/news/2015/first-fast-charging-electric...

Then neighbouring Helsinki:

https://www.hsl.fi/en/news/2017/helsinkis-first-fully-electr...

It's very small still, of course, but seems to progress without major problems. (They make a point about the exceptional arrangement for the risky investment, i.e. the municipal company bought and operates these buses themselves; normally they just organize the procurement of transport services from private companies who own the buses and hire drivers.)