Without having read the paper, my first counterargument would be like this: Yes, fossilization is rare. But industrialization is a wildfire. A spezies undergoin

Without having read the paper, my first counterargument would be like this: Yes, fossilization is rare. But industrialization is a wildfire. A spezies undergoing this would multiply like crazy and there would soon be hundreds of millions of the same exact species around. That's just talking steam power. Going to space? Hard to believe they'd achieve that without reaching a billion or more. Assuming similar productivity of course. Hundreds of millions, much less a few billions individuals of the same exact creatures living and dying would lead to a rather distorted fossil record, wouldn't it? Even if they used cremation, they should still be distorting the fossil record just from those bodies that "fall aside" somehow. Also because they'd need domestic animals and they'd kill off or supress other macrofauna. They would have to be giant squids to not leave behind MUCH of a fossil record, and then survive against the biggest and baddest dinosaurs...