Among other possibilities, as an example, this Open Assistant chat interface was written mostly in Python, as evident on the project's GitHub page (https://github.com/LAION-AI/Open-Assistant). Python is also widely used for training AI models. The language is complex enough to accommodate most commercial projects, not only the personal or individual ones. You would only need another language for special case domains, like systems programming (drivers, operating systems) or web applications for browsers without WebAssembly support.

The Ren'Py game engine is a very popular Python project that has been used for a large number of games, including the widely acclaimed and commercially successful game "Doki Doki Literature Club".