They may have no interest or perceive no benefit at the present time; I can certainly understand that view. However, they need to evaluate the long term considerations. Although some areas may not have wanted Interstates when they were built, I doubt that many now would remove them if they could. There are myriad transportation efficiencies, commerce advantages and even social conveniences that develop around highway use. This is not to downplay any associated problems, but you don’t want to ignore possible advantages either.
I don’t think many rural counties could financially support the full cost load of construction and then maintenance (including all the rebuildings that have occurred since the 1950s/1960s) of even one interstate crossing the county.