“Because the OV-10 is one of the best light attack and close air support aircraft ever built.”
Because it was one of the only times the close air support community actually got a real say in how a plane should be designed.
The OV-10's STOL capability was demonstrated when it landed and took off from one of the Navy's carriers without catapults or arresting gear. Simply put, the OV-10 and the A-10 Warthog are the two best CAS aircraft ever built. We need more of them in updated versions, but they can do the jobs the Mach 2 fighter mafia cannot do or would rather not do; that is, the CAS mission.