That’s the naive assumption, but we have had massive car park fires in times when EVs were much less prevalent:

https://www.bbc.com/news/uk-england-merseyside-46290095

And research into car park fires in post-EV times may also not support that theory:

https://www.ri.se/sites/default/files/2020-12/FRIC%20D1.2-20...

> Electric vehicles: Observations during the fire indicate that electric vehicles did not contribute to the fire development beyond what is expected from conventional vehicles.