The issue isn't the material, but the size FOR the given material. Polymer pistols usually have much thicker frames than a 1911, even if just to hold steel bits that serve as the wear surfaces. I wouldn't trust a polymer 1911 frame that was true to dimensions. Even the Wilson is significantly thicker.
.45 and 9mm are old (1900s) relatively low pressure cartridges. The .40 was designed from the beginning (1980s) to be much higher pressure. It's the reason Sig changed from the Model 228 to the Model 229, to make a gun the same size that wouldn't get beat to death by adding the .40 to the lineup.