That's what they're supposed to do, though, according to Tesla[1]. The firefighters are there to pour water on the fire to cool it down and wait for the battery to burn and release its energy. This is what Tesla's manuals[1] say:
> If the high voltage battery becomes involved in fire or is bent, twisted, damaged, or breached in any way, or if you suspect that the battery is heating, use large amounts of water to cool the battery. DO NOT extinguish fire with a small amount of water. Always establish or request an additional water supply.
> Battery fires can take up to 24 hours to fully extinguish. Consider allowing the vehicle to burn while protecting exposures.
EV battery fires and their risk to firefighers are a national problem[2].
Also, you're expecting a lot from what are often volunteers who have little to no funding. I lived in a place where over $20 million was spent on police salaries each year, but firefighters and EMTs were all volunteers.
[1] https://www.documentcloud.org/documents/20805805-2014_model_...
[2] https://www.nbcnews.com/business/autos/federal-regulators-wa...