For me, the interesting point is that these complex organics have formed courtesy of the various stellar processes and have found their way into galaxies, interstellar space and also maybe planets, certainly moons. Titan is a classic example of a huge repository of liquid hydrocarbons .. right within our own system. If Titan had some oxygen and someone lit up a match within its vicinity, it'd probably engulf the entire planet in rapid combustion.
So, who is to say that the Earth didn't acquire this class of organic compounds courtesy of the same processes ? It is actually starting to seem quite likely with these spectroscopically confirmed observations. And also, who is to say that some of the sub-processes at the tail-end of all this, ceased over a 5 billion year planet formation period ? Apart from the nucleosynthesis part, why couldn't these still be occurring right now, right under our feet ?
Also, apart from the standard mainstream answers, is it possible that this may be why some oil wells replenish themselves ? (Admittedly some don't also). Other scientists have actually followed this line of enquiry and somewhat surprisingly, there are 'pros and cons', evidence 'for and against' either view on the origins of what we all call 'fossil' fuels.
I think it would be hilarious if it turns out that the origin of our fuels had nothing to do with the ol' rotting fish story.
(That's my pseudoscientific contribution for today .. better get back to mainstream .. quick …
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Cheers