Well, this repo is definitely about data analysis pipelines and not about production trading systems, no one is arguing that writing live prod trading systems i

Well, this repo is definitely about data analysis pipelines and not about production trading systems, no one is arguing that writing live prod trading systems in Python is inappropriate. And in order to write "new analysis" in another language, you would need to have access to the ecosystem that's been already developed in Python (both internally and externally), even to just get as far as loading all the data from all the data sources you need. Also worth a mention, "Python" often really means "C++ wrapped in pybind or the like"; again, it's pretty hard to match if there's a developed ecosystem of C/C++ libraries and extensions.