Comment by dajonker

Well said. There are many problems you have to deal with when writing code and type annotations only solve one particular kind. And even type annotations can be wrong: when you're dealing with data from external sources, dynamic languages like Python, JavaScript and Ruby will happily parse any valid JSON into a native data structure, even if it might not be what you specified in your type hints. Worse yet, you may not even notice unless you also have runtime type checks.

The kind of messy code base that results from (large) numbers of (mediocre) developers hastily implementing hacky bug fixes and (incomplete) specifications under time pressure isn't necessarily solved by any technical solution such as type hints.