Dynamic typing is from 1958 Lisp. Your history is off a bit there, by some forty years.

The 90's also saw much commercial experimentation with visual environments (e.g. Visual Basic, Delphi, JBuilder) with round-trip conversion between the layout form and underlying code. They were promoted for R.A.D. (rapid application development -- remember that acronym?) but, like dynamically typed languages, they also had sustainability issues.

Of course, like dynamic typing and Lisp, visual environments also had Smalltalk from way back, but they were before big business became infatuated with the ideas.

How do products like Delphi have sustainability (maintainability ?) issues ? Delphi/Object Pascal is statically-typed, so you can't even build an application that has issues with the code-behind for a form.

You can see errors at run-time from mismatches between the code-behind and the forms, but this has nothing to do with the language. It's just the way that certain products like Delphi decided to handle such mismatches. You'll see these types of issues with any code that performs run-time serialization/deserialization of class instances. Our product, Elevate Web Builder, uses a similar architecture with its WYSIWYG form designer/forms (they use JSON instead of a custom key-value format), but it simply ignores properties in forms that don't exist in the actual code.

Lisp has nothing to do (in many ways) with the late 80s and 90s wave of dynamic languages.

JavaScript was definitely partly inspired by Scheme.

likewise ruby by lisp

I’d say Ruby’s closest sibling is Smalltalk personally.

People say this mainly because of the brace-enclosed blocks of code being functions. However, that is really just a syntactic sugar for lambda (and can even have explicit arguments: (lambda (x y) ...) <--> {|x,y| ... }.

there's the "everything is objects and messages sent to them" bit too, which is definitely from smalltalk. ruby took the good bits from several languages.

I've still not seen a single "sustainability issue" in Python code bases which seem to stem from dynamic typing as opposed to static typing.

I think Elixir is trending, and it's not statically typed, right?

That said, I do agree that static typing is in vogue.