For small programs, dynamic typing can be faster to write (not read). As soon as your program grows: "uh oh". Once you add maintenance into the cost equation, dynamic typing is a huge negative.

To be fair: 15 years ago, people were writing a lot of Java code that effectively used dynamic typing by passing around Object references, then casting to some type (unknowable to the reader) when using. (C#: Same.) It was infuriating, and also very difficult to read and maintain. Fortunately, most of that code is gone now in huge enterprise code bases.