They are not producing enough revenue to pay for needed maintenance and upkeep. Others are badly in need of improvements to make them viable and efficient. Airport managers are charged with doing the best they can with the resources available.
Safe operation is the first priority.
With a limited staff, other needed work may be postponed or simply never completed. This is where airport supporter volunteers can help by forming an Adopt an Airport group. Working in cooperation with and under guidance of the airport manager, volunteers can perform many functions that might not otherwise be done. Many airport supporters have special skills that they would employ as volunteers.