Because automatic refactoring tools are not available for dynamically typed languages, programmers are more hesitant refactorings. So the technical debt accumul

Because automatic refactoring tools are not available for dynamically typed languages, programmers are more hesitant refactorings. So the technical debt accumulates and the code gets worse because of that death spiral. That's what I mean when I said that dynamically typed languages crumble under large code bases.