I think your c 14 and other possible decay rates is wrong, I will look into it to be sure. The point is, when the laws of physics allow the possibility of variables, unobserved phenomena in the past cannot be assured to be compliant with phenomena today. At best, you can say we believe. That's called a theory, not fact.
The way that the assumptions and pronouncements of science are confirmed is by how well they let us predict and at times control outcomes. That's really all we need out of theses ideas. Philosophical musings about absolute truth are irrelevant. Does the hypothesis get us to the moon and back, or prevent smallpox? If yes, the ideas are good ones.
The basis of this thread is atypical creationist attack on science based on a finding that was unexpected. At other times, it's based on what has never been seen or what isn't yet explained.
Empirical adequacy is the term used to describe an idea that unifies observations, offers an explanatory mechanism, makes predictions that are never falsified about what can and cannot be found in nature if the theory is correct, and has technological applications that improve the human condition. That's as good as it gets or can get, and evolutionary theory rises to that standard with flying colors. Religion does not.
Why on earth would we toss out an idea that can do so much and replace it with one that is sterile - that explains nothing, offers no mechanism, has no supporting evidence, predicts nothing, and has no practical application?
Here's the problem with all of the "you can't be absolutely sure" arguments:
As Descartes explained, we don't know for sure that there is a world outside of our minds. But if we assume that there is, or behave as if there were such a world, and experience the results that we would expect to experience if we really had a body that was really in an a world of other objects operating under what seem to be the rules of an actual universe, then that is all we need to proceed as if our assumptions are valid.
Even when we know that a model such as Newton's formulation of gravity is incomplete, we still use it except when dealing with the extremes under which the variation between prediction and observation are too great. Newton's work was sufficient to get man to the moon and back.
This is what the empiricist is focused on, not whether it can proved beyond a shadow of a doubt that the laws of physics apply everywhere at all times since the first fraction of a second after the Big Bang, or that there is indeed an actual world out there revealed to us by our senses. If an assumption leads to conclusions that work for us, then that's good enough, and confirms the assumption as best as it can be confirmed.
You can't sell alternative ideas that can't do that unless you're talking to somebody that doesn't care if his ideas are useful.