You yourself seem to suggest that it is more related to the sheer size of freeways and interstates that make open-graded mixes cost-ineffective, which I agree with.

No, what I said is that you can absolutely use open asphalt outside of freeways, but that the benefit is smaller. Whether or not you want to do it all depends on how you weigh your cost-benefit analysis. Many Dutch cities use it in the city for noise reduction, regardless of higher cost. But if you value things like noise and splash reduction less, then the cost-benefit will land more solidly on "don't build expensive things".