That is true but some 1-A schools - 3A schools have anywhere from 6-9 towns to make that school.
Examples:
IKM-Manning
Irwin, Kirkman, Manilla, Manning, Aspinwall, Botna, Defiance, Fiscus, Gray, Red Line
Harlan
Harlan, Defiance, Kirkman, Earling, Westphalia, Panama, Persia, Corley, Tennant
With the combination of so many school, open enrollment exploded since towns like Kirkman are a lot closer to Harlan than Manning but Kirkman's taxes still go to IKM-Manning.
I still predict that in the next decade, all smaller schools will start closing and each county will only have only 1-2 schools. So all students in Shelby county will go to Harlan, Carroll county will go to Carroll High or Carroll Kuemper, etc...