ICD and simulation should both be mandatory. As also debug using print statements, or LEDs/GPIO.

But knowledge about splitting a problem into smaller and smaller pieces until faulty pieces can be identified should also be mandatory.

And that it helps to program by contract and start directly adding code that tests required conditions - this code can optionally be removed or conditionally compiled away when getting close to release. But the reverse: to write everything and debug, and first when it works add error handling is a common way people write programs. Which means they don't have any help during the debugging.