Yes, a numerate population as assessed by national averages matters. A more numerate population reasons better about economic policies and may vote more wisely. Numeracy is closely tied to the ability to work in a variety of occupations. If we consider probability and statistics, the implications are especially salient.

>A more numerate population reasons better about economic policies and may vote more wisely.

People with good STEM education, even with PhDs in that field aren’t necessarily competent voters and good decision makers outside of area of their interests. Understanding economic policies is still an effort that many aren’t willing to take.

This seems to me more like a reasonable hypothesis than a foregone conclusion.

Personally I suspect there's a floor (can read a chart, understands growth rates and compounding in general) which the public need to assess arguments constructed by specialists, while the rest is mostly understanding ideology.

The reason I believe that is, I think I can pretty much predict 100% of the conclusion of most articles written for the public by knowing the names & affiliations of the authors and the topic. The only uncertainty is what sources and statistics they will pick to reach the conclusion required by their ideology.

A numerate and literate population matters for many reasons, but in theory it’s possible to field a strong team for the Olympiad despite an abysmal national average literacy level. Just look at North Korea for example. They’ve got a “fat right tail” of sophisticated hackers but on average their literacy is terrible.