Comes as a big monolithical block that's much harder to work with if you have to develop bigger systems, language tooling is lacking even compared to something

Comes as a big monolithical block that's much harder to work with if you have to develop bigger systems, language tooling is lacking even compared to something like Python that's already mediocre, in many aspects (data analysis/data engineering, machine learning, etc.) isn't as good as other options like Python or R. It's also not great as a general purpose language. It was never meant as such of course, but working in a real language where I can take stuff off a notebook and have it become a script has its advantages. Finally, I'm willing to use open-source software that's slightly worse if the difference isn't huge, and for many use cases the difference isn't huge. For some it is, and that's where Mathematica is great.