That and the fact that most of the readily available organic ones break down under the types of heat involved rather quickly.

The oil film on the cylinders at least lasts a surprisingly long time provided the pistons in motion and you don’t try to restart the engine. You can famously drain the oil out of an already running engine and it’ll continue to run happily for quite some minutes afterwards — until you shut it off. This was a popular demonstration trick for engine additive snakeoil (literally) salesmen back in the '70s and so on. “See! Our miracle oil additive is so effective your engine can run without oil at all after treatment!” Never mind the fact that it would do so anyway, and don’t expect it to work twice.