Having worked with Smalltalk a lot I think I know what its main flaw for industrial software development is. It is the image, and your ability to change anything in it (easily), like the Compiler for instance. Then you save your image. Your image is no longer compliant with anybody else's image and the programs you develop "on it" will not run on anybody else's image.

Compare this to a language like JavaScript. There too you can modify the base-objects like Object and Function and Array. But the changes you make to them will be part of your program which is not saved as part of an "image" (only as source-code). Your JavaScript program does not assume anything more about its environment than anybody else's JavaScript program, because you can not develop against a modified "base-image" (since there is no such thin in JavaScript, is there?).

Smalltalk would be great for things like programming all the smart devices in your house. I think that was part of its original goals, provide an environment where everybody can create their own programs, without worrying much about how your program might later integrate with programs of others.