It may be surprising, but Idaho actually had pretty decent infrastructure throughout my youth. This "defund everything" attitude is relatively new to idaho politics. Idaho's drift into libertarianism started around the tea party era and just slowly has gotten worse since then.
I realize libertarians by nature have unique viewpoints but that feels like a bit of a mischaracterization. In general libertarians support a smaller government that increases focu on areas where societal collaboration is strictly necessary like roads, police, and firefighters while by default opposing government involvement in other areas beyond baseline rule of law (like NIMBY zoning).