Starting a fire or crashing a small plane/car are completely orthogonal situations.
Your sources point to weather/climate as the causal source of wild fires.
> Small-airplane fires have killed at least 600 people since 1993, burning them alive or suffocating them after crashes and hard landings that the passengers and pilots had initially survived, a USA TODAY investigation shows. The victims who died from fatal burns or smoke inhalation often had few if any broken bones or other injuries, according to hundreds of autopsy reports obtained by USA TODAY.
> Fires have erupted after incidents as minor as an airplane veering off a runway and into brush or hitting a chain-link fence, government records show. The impact ruptures fuel tanks or fuel lines, or both, causing leaks and airplane-engulfing blazes.
> Fires also contributed to the death of at least 308 more people who suffered burns or smoke inhalation as well as traumatic injuries, USA TODAY found. And the fires seriously burned at least 309 people who survived, often with permanent scars after painful surgery.
And while that is about dangers for an occupant it should be noted that a fire from a small airplane crash is not a rare occurrence.
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https://www.aopa.org/training-and-safety/students/flighttest...
> Aircraft fires often occur following forced landings, and the result is often more dangerous than the forced landing itself. The sad truth is that most light aircraft fuel systems are not designed to withstand crash impacts, and they often fail during a forced landing. Spilled fuel and hot crash components often result in a fuel-fed inferno.
Note the word often there.
If you take a look at the numbers, only a ratio of 0.04 accidents result in a post-impact fire. It's rare.
As you suggested, I noted the word "often," in return please note 0.04.