Ruby isn't Smalltalk. The only thing Ruby inherited from it is the pure object model. Everything else was cribbed from other languages. Ruby doesn't have what makes Smalltalk great, the image-based development model.

I'm making my own text editor in Ruby now, as I'm wishing for a more Smalltalk-like experience with it. There's just so much missing. Ruby has the reflective capability to enjoy a Smalltalk-like IDE, but Rails took over and drove Ruby in that direction long before anyone could cook one up.

Which is a shame, IDEs that aren't Smalltalk / Lisp haven't graduated past the need for static analysis despite having 50 years to do so. Now it's the red-headed stepchild of languages due to no fault of its own.

As someone that used Smalltalk via Smalltalk/V back in the day, I would nonetheles vouch that dev environments with direct connection to Smalltalk, like Java and .NET, are the closest we get to it in mainstream languages.