[jasode]

In both cases of Javascript and Objective-C, programmers didn't deliberately choose "dynamic" as an explicit engineering design.

Even though the Apple System9/OSX platform has been around a long time, the Apple ecosystem got really popular with the iPhone & iOS in 2007. From 2007 to 2014, the official SDK for that was Objective-C. Obj-C is dynamic, and as a consequence, people happened to program in a dynamic language. ("When in Rome do as the Romans...")

Same situation for web browsers. The only "sdk" for adding interactivity and actions to web pages was Javascript -- which happened to be "dynamic".

In other words, "dynamic" was something programmers had to live with rather than something they chose for architectural superiority.

In both cases (Swift, TypeScript), the desire for static typing became apparent.