Scientific computing. I can't just write a "for" loop and expect it to perform. I have to use whatever is provided by packages which weren't written in it, or m

Scientific computing. I can't just write a "for" loop and expect it to perform. I have to use whatever is provided by packages which weren't written in it, or make a similar package myself. I can't imagine any technical reason for this situation. Only perceived convenience and some kind of social dynamics.