You say I'm being hypothetical but I back up what I'm saying with examples when you don't. What high cost do you mean? The extra time you spend writing type an

You say I'm being hypothetical but I back up what I'm saying with examples when you don't. What high cost do you mean? The extra time you spend writing type annotations and getting your program to compile is time you save puzzling through runtime errors. Python, JavaScript and even PHP all have ways to get static checking from the use of types. Why would you not want to take advantage of this and rely on less reliable dynamic checks instead?