Why is the mesh not rendering?

I am working through a tutorial here. I think I can share the package through my google drive for convenience.

I have set up a scene that looks like this:

The subject object is HexGridController and three objects that are disabled: center_fill, Backdrop, DiagnosticDisplay.

The grid controller is an otherwise empty GameObject except for attached script:

...and the HexGridController script:

 public class HexGridController : MonoBehaviour, IGridInterface {
 
     public float cellWidth = 50F;
     public HexOrientation cellFacing = HexOrientation.Acute;
     public int cellCols = 20;
     public int cellRows = 14;
     public float degOffset = 0.0F;

     // ... snipped IGridInterface implementations
 
     // Use this for initialization
     private void Start () {
         print("Hexagonal Grid Controller started");
 
         print("hex vertices:");
         int idx = 0;
         foreach(var vert in vertices){
             print(string.Format("\t[{0}]: {1}", idx, vert.ToString()));
             ++idx;
         }
     }
 
     #region    HiddenInInspector: vertices, uv, triangles
     [HideInInspector]
     public static Vector3[] vertices = new Vector3[]
     {
             new Vector3(0f, Hexagon.floor, 1f),        //    north
             new Vector3(1f, Hexagon.floor, .5f),    //    northeast
             new Vector3(1f, Hexagon.floor, -.5f),    //    southeast
             new Vector3(0f, Hexagon.floor, -1f),    //    south
             new Vector3(-1f , Hexagon.floor, -.5f),    //     southwest
             new Vector3(-1f, Hexagon.floor, .5f),    //    northwest
     };
 
     [HideInInspector]
     public static Vector2[] uv = new Vector2[]
     {
         new Vector2(0.5F,1),    //    north
         new Vector2(1,0.75F),    //    northeast
         new Vector2(1,0.25F),    //    southeast
         new Vector2(0.5F,0),    //    south
         new Vector2(0,0.25F),    //     southwest
         new Vector2(0,0.75F),    //    northwest
     };
 
     [HideInInspector]
     public static int[] triangles = new int[]
     {
         1,5,0,
         1,4,5,
         1,2,4,
         2,3,4
     };
     #endregion
 }

And finally, HexGrid is a GameObject with the following script attached:

 public class Hexagon : MonoBehaviour {
     private MeshRenderer meshRenderer;
 
     public const float floor = 0;
 
     public HexGridController grid;
     public Texture texture;
 
     // Use this for initialization
     private void Start () {
         print("Hexagon started");
 
         HexGridController.vertices[0] = new Vector3((grid.cellWidth * Mathf.Cos((float)(2*Mathf.PI*(1+0.5)/6))), Hexagon.floor, (grid.cellWidth * Mathf.Sin((float)(2*Mathf.PI*(1+0.5)/6))));
         HexGridController.vertices[1] = new Vector3((grid.cellWidth * Mathf.Cos((float)(2*Mathf.PI*(0+0.5)/6))), Hexagon.floor, (grid.cellWidth * Mathf.Sin((float)(2*Mathf.PI*(0+0.5)/6))));
         HexGridController.vertices[2] = new Vector3((grid.cellWidth * Mathf.Cos((float)(2*Mathf.PI*(5+0.5)/6))), Hexagon.floor, (grid.cellWidth * Mathf.Sin((float)(2*Mathf.PI*(5+0.5)/6))));
         HexGridController.vertices[3] = new Vector3((grid.cellWidth * Mathf.Cos((float)(2*Mathf.PI*(4+0.5)/6))), Hexagon.floor, (grid.cellWidth * Mathf.Sin((float)(2*Mathf.PI*(4+0.5)/6))));
         HexGridController.vertices[4] = new Vector3((grid.cellWidth * Mathf.Cos((float)(2*Mathf.PI*(3+0.5)/6))), Hexagon.floor, (grid.cellWidth * Mathf.Sin((float)(2*Mathf.PI*(3+0.5)/6))));
         HexGridController.vertices[5] = new Vector3((grid.cellWidth * Mathf.Cos((float)(2*Mathf.PI*(2+0.5)/6))), Hexagon.floor, (grid.cellWidth * Mathf.Sin((float)(2*Mathf.PI*(2+0.5)/6))));
 
         SetUpMesh();
     }    
     
     private void SetUpMesh() {
         MeshFilter meshFilter = gameObject.AddComponent<MeshFilter>();
         gameObject.AddComponent<MeshRenderer>();
         meshRenderer = gameObject.GetComponent<MeshRenderer>();
 
         Mesh mesh = new Mesh();
         //vertices
         mesh.vertices = HexGridController.vertices;
         //triangles
         mesh.triangles = HexGridController.triangles;
         //UV vectors
         mesh.uv = HexGridController.uv;
      
         //recalc for lighting
         mesh.RecalculateNormals();
  
         //game object's mesh filter
         meshFilter.mesh = mesh;
  
         //set to null when not testing
         meshRenderer.material.mainTexture = texture; 
     }
     
     private void Update () 
     {
         
     }
 
     private void OnDestory()
     {
         Object.Destroy(meshRenderer.material);
     }
 }