Completely agree with 4 and 5. I use Julia regularly and while it is great for scripts and proof of concepts of mathematical stuff it might be too complicated to implement in Python or in C++ once one starts to grow an application it is tremendously frustrating.

I have clear and satisfying workflows in C (vim + make + gdb + valgrind) and Python (vim/vs code, pdb) but I cannot say that debugging and tracing errors is a comfortable experience in Julia. Essential development tools are relegated to third-party libraries (e.g. Revise.jl and Debugger.jl) and are often clunky or responsiveness is limited (e.g. Revise.jl won't work when you change a struct)

I believe the problem is that, because of Julia is marketed towards scientific computing and HPC, it draws mostly from an academic user base which is not that interested in software development.