This puts a lot of extra conditions on the runtime; you basically have to implement a "dynamically typed" runtime like Javascript. In doing so you lose a lot of performance. Google have invested something like a century of man-hours into V8 and on typical benchmarks the performance is about half of Java's, which in turn is typically about half of C / Rust's performance. That's a pretty big compromise for some.

This is basically what we already have in Haskell. Debug functions that sidestep the typing system can be annotated with a warning and you can make this one an error while compiling for production.

And in a more general sense, you can ask the compiler to forbid escape hatches altogether.

We already have a pragmatic, reliable solution.