Smalltalk images offered introspection, debugging of running processes, etc., but some of the later features listed seem quite impractical to add to the language. "Record the entire program execution," for instance.

That's more or less the point the author makes on the next line: "Different tools support different features and have different limitations." The ideal debugger does not necessarily make for the most ideal programming environment, just as a plane made out of steel is great for structural stability but may not be a good plane.