"You keep saying that I need to show you this. Why?"
Because that is the measure, ultimately, of any scientific theory--its predictive value. If it does not have better predictive value than a competing theory, the competing theory wins.
Yes, it's survival of the fittest.
And what if both theories are roughly equivalent in their predictive value?
Yes, it's survival of the fittest.
Which is why ID claims that biological systems should be looked at to determine if they could have evolved naturally or had to be created by some other mechanism is good science. It tests the fitness of both theories. How is believing that evolution is a settled matter and that it's a waste of time challenging it with alternate theories better science than testing it to see if evidence can be found of a non-natural mechanism at work in the process?