Why have glass and plastic plagued Android phones? What is the reason for not using higher quality materials?

Why have glass and plastic plagued Android phones? What is the reason for not using higher quality materials?

While Today It Is Possible To Produce Phones With Various Materials Such As Titanium, Cobalt, And Sapphire, And Apple Uses Stainless Steel In The iPhone, What Is The Reason For Continuing To Produce Android Phones…