But Smalltalk is not a language.
Yes, it is. GNU Smalltalk is a command-line Smalltalk without the IDE. The (now-defunct) Redline project was a Smalltalk for the JVM; it, too, didn’t have an IDE. Hoot Smalltalk, also for the JVM, doesn’t have an IDE.
The IDE’s have very high learning curve
The Smalltalk IDE is much simpler, much cleaner, and much easier to learn than, say, Visual Studio or Eclipse or Xcode. I’ve used all of them, and I found VS, Eclipse, and Xcode very intimidating. And this coming from a senior software engineer with over 20 years experience!
I hope someone will figure out a way to take this language and bring it to reality; remove it from its IDE let people choose and add few language extensions.
Methinks you do not understand the Smalltalk ethos. From the very beginning, Smalltalk was envisioned as a new programming model, different from the one that everybody was used to (i.e., working with files, folders, command line, and long reams of code). Smalltalk was designed for easily accessible live coding, something you don’t find in VS, Eclipse, Xcode, or any other modern IDE.
The strength of Smalltalk is that you have a language, IDE, and total system of live objects working together harmoniously to deliver efficient development. Live coding practically eliminates the traditional edit-compile-test-debug cycle that has hampered developers for over half a century. In fact, it is not uncommon for Smalltalkers to do all their development inside of the debugger!
In other words, Smalltalk is the epitome of software development synergy (my term). It is this synergy that makes Smalltalk supremely productive. Who wouldn’t want to cut their development time in half?!
What you’re proposing is to discard this synergistic development, and along with it, the tremendous productivity boost. If you truly want this, you can have it. Like I said, GNU Smalltalk can be used with any third-party tool you like.
And, by the way, Smalltalk is great for adding language extensions. It has a fabulous metaprogramming capability. Moreover, Leandro Caniglia has been writing a great series of articles for extending Smalltalk syntax — see https://smalltalk.tech.blog/.