In the Woburn hypo (or similar), if we think that it's a problem that each element, added together, does not amount to 51% as a whole, then I think more weight should be given to the fault element. If the fault can be established, then I am not so concerned with the actual causation. Penalizing that company still serves the public policy goals of deterring negligent/potentially harmful conduct.
Of course juries cannot be certain about their verdicts. We cannot be "certain" about anything. We are trying to do the best we can. What's our alternative? If our inability to know something with 100% certainty were to prevent us from acting based off of knowledge that hits any degree lower than that, then we wouldn't accomplish anything as humans.
Larry Bird as the greatest ever was a hot take. But, really, it makes sense to go through the elements in a process and to think through the likelihood of each of the elements. However, it's an almost-unworkable solution if you have to be >50% sure of each element since that quickly can make it an almost unreachable hurdle. Moreover, it risks casting doubt onto the system and inviting greater scrutiny to the jury system.
Successive probability depends on the claim that the events are independent. There is a large amount of evidence that suggests seemingly independent events are actually dependent and that humans are not very good judges of independence.
I wonder whether the reason why we accept a lower cumulative probability than preponderance is because we don’t really weigh the importance of these elements equally or because we feel that distinguishing and ensuring that each element is there is more important than cumulative preponderance
Compounding elements in a trial necessarily leads to fewer cases of absolute certainty. But some cases are complex. If it seems too difficult for a jury to accurately consider compounding elements, maybe different questions should be tried separately by different juries.
I don't think that probability is the bare question that society wants the jury to determine. The jury is to make a social judgment -- one inflected by probability, effects of the alleged acts, strength of evidence, status of the parties. I think it's okay that a human system largely runs on human intuitions.