Code can destroy original obstacle, but can't destroy clones

[TITUXS]

Why it can’t destroy clones?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Obstacle : MonoBehaviour
{
    private float leftBound = -15;
    private PlayerController playerControllerScript;

    public GameObject obstaclePrefab;
    private Vector3 spawnPos = new Vector3(-3, 2, -10);
    private GameObject prefabPosition;

    // Start is called before the first frame update
    void Start()
    {
        playerControllerScript = GameObject.Find("Player").GetComponent<PlayerController>();
    }

    // Update is called once per frame
    void Update()
    {
        if(transform.position.y < leftBound && gameObject.CompareTag("Obstacle")){
            Destroy(gameObject);
            prefabPosition = Instantiate(obstaclePrefab, spawnPos, obstaclePrefab.transform.rotation);
        }
    }
}