That seems like an argument to me.
You could counter that America was filled early on with particularly zealous types, and that it's a big enough country that the science and the religion could find their own areas to bloom separately, but that may actually be supporting his argument.
> science will not destroy it
That's making two statements, not arguing that those two things show the points in the title. Maybe those two things are an accident? Maybe they're unrelated to the conclusions. To make an argument they'd have to argue why they support those conclusions.
By numbers of Nobel prize winners?
By numbers of practicing researchers?
By numbers of technological and scientific jobs?
By the presence of advanced technological infrastructure?
I mean there are tons of ways to "quantify such a thing", and in most of those America comes close to the top or at the top.