Many Smalltalkers have used it for IoT applications. I'm not sure what your problem is.

I've used it for web applications. I've never needed multithreading, but then my web applications weren't particularly demanding.

Smalltalk continues to be used by thousands of enterprises around the globe. They keep Cincom, Instantiations, and GemTalk Systems in business.

In many respects, Smalltalk is similar to Python and JavaScript and Ruby.