That is a really good question, tbh. I've seen comparisons that show the Tesla's burning less often, but those weren't specifically post crash. A lot of ICE cars come from fuel leaks, often after major repairs and without a collision.

I'm not aware of a direct comparison of post-crash fires. Anecodally, it seems the post-crash fires are rare with the 3 and Y and much less rare with the S/X.