There are several firms that I personally know of that use alternative languages for building production systems around AI. My two largest clients have systems built in Typescript and Java. If you are going to work in this field you have to know Python as it is a common language for practitioners, but the language choice for production systems is driven by many factors. Python is almost never an appropriate choice for building production systems. Even in cases where we use Python for models, the models are exported to a different language for integration with the deployed application. In many cases there are substantial benefits to building models in the language that will used for building the final application as well. As with all technical choices, the needs of the project should be the ultimate basis for making a selection -- not fanboi attachments to particular languages.

> but the language choice for production systems is driven by many factors. Python is almost never an appropriate choice for building production systems

And JS is? Even with TS papering over the top of it, JS is not really an ideal language for this. If you want a type system, performance and ease of use, why not write it in Julia?