Focused more on the following response, I would note it was initially good if somewhat ineffective.
The pilot self-evacuated and was fortunate to be able to do so. Building fire extinguishers are ineffective (and so shown) in this situation. I assume 911 was initially called but the only thing that will extinguish that fire will be engines with sufficient water and/or foam. The pilot survived because he was not entrapped, whatever good intentions those at the airport may have had.
Agreed. With the pilot out of the plane and no one else onboard, and the size of the fire by the time someone showed up with a likely 5 or 10lb ABC, it’s useless to try and fight it, for just property now. And with 30 or so gallons of Avgas in close proximity just waiting to ignite. With no turnout gear, very limited firefighting equipment, and a high potential of Class B ignition and flash, best to just let the thing burn by that point. Trying a quick shot with the extinguisher like you can see having been done is fine, but if that doesn’t work, back off and be done with it, for their own safety.