Being able to understand a system under fire with minimal tooling available is a property one must design for. If you get woken up at 3am with a production outage, the last thing you want to do is start digging through some smart-ass framework's idea of what is even running to figure out where the bug is.

There's nothing wrong with using an IDE most of the time, but building dependence on one such that you can't do anything without it is absolute folly.