The work to have the type system do stuff for you doesn't happen for free. You need to define a whole bunch of scaffolding to support the application functionality. Sure, once it's set up, using it can be pretty painless, but the design, implementation and testing of the supporting code is a non-trivial effort.

In contrast, Python (and other dynamically-typed languages) avoid all of that.

In addition, the compile-time cost of all this is significant. Cup-of-coffee builds are a definite burden on productivity.