Unity replace standard shader

Recently, when optimizing the memory, I found a shader with a very high memory
usage that is too bad. G
Observed by Profiler, shaderlab occupies 273M, which is very high (for a small project, only a few shaders are used in total).
The most used shader in the project is standard
. I did a test and replaced the standard

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

public class ExchangeMaterials : MonoBehaviour
{
    
    
	[MenuItem("Tools/ExchangeMaterial")]
	static void ExchangeMaterials()
	{
    
    
		var allMaterials = AssetDatabase.FindAssets("t: Material");
		foreach (var guid in allMaterials)
		{
    
    
			var path = AssetDatabase.GUIDToAssetPath(guid);
			Material m = AssetDatabase.LoadAssetAtPath(path, typeof(Material)) as Material;
			if (m != null)
			{
    
    
				if (m.shader.name == "Standard")
				{
    
    
					m.shader = Shader.Find("AAA");
				}
			}
		}
	}
}

Find out all the standard in the project and replace them with test shaders. At this time, I found that some shaders could not be taken out and replaced.

After scratching my head for a while, I found that it was related to the settings of FBX import.
Setting parameters like this will generate a material that comes with the model, and you can change the shader La

After repackaging, I found that the package output speed was many times faster. I had a premonition that I must have found the direction this time. O(∩_∩)O haha~ After running, the
memory has been reduced by 600M+, and the memory has finally dropped. I also have lingering fears. I didn’t expect A small detail that was not observed takes up so much memory! ! ! Look at Profiler at this time, shaderlab occupies only 1.1M,,,