You do make some valid points but I wouldn't want to work on any kind of large scale codebase that used Javascript over Typescript. Even working in a Typescript codebase of hundreds of thousands of lines I've seen poorly named functions returning data types you wouldn't expect and poorly named variables. I can only imagine the hell if it was a pure javascript codebase and the actual types these things were returning weren't defined somewhere and you had to rely on the debugger for everything or delve through the codebase. Now your IDE catches it before you even run the code. I suppose if we were trying to extend this to the analogy, it's more productive and economical for any company with a substantial fleet of vehicles to run the newer models than it is trying to keep the old ones on the road.