we’ll never know for sure what did it.--- be careful with that kind of thinking. Bear in mind the head of the US Patent Office who, near the turn of the last century, said they should close up the USPO because everything that can be invented, had been.
Or closer to the thrust of the thread, prominent scientist Auguste Comte, who wrote in 1842 that it was impossible we should ever know the composition of stars. Less than thirty years later, the science of spectroscopy was developed.
But those involve scientific observations about the present and/or future. Science of the past is a lot more speculative. Paleontology and archaeology run into the same problem; unless a dinosaur steps out of a time machine and says “No guys, this is how we went extinct,” we will never know for sure and much of it is simply guesswork. I’ve heard dozens of theories about the extinction, and new ones are always popping up. Even if we definitively solve it, some joker scientist will come along with a new theory with new evidence that casts doubt on the official explanation. Here we go again!