Dunno ... I would call “knows how to install Perl modules” merely the work of an apprentice .. not even a journeyman. A developer is someone who designs computer software, not just implements it: this is a creative process, not just a rote task. “There’s More Than One Way To Do It™” carries many meanings and implications.
I do not know of anyone who did not acquire their pragmatic education “on the job, and nowhere else.” In the not-so old days of trade work, you
signed on indentured yourself as an apprentice and you schlepped a lot of trash-bins and (very carefully) cleaned up the metal tailings around the lathes, and you learned by watching and doing. To say that the job consisted merely of knowing what knobs to turn and what buttons to push is to ignore the value of experience. I always suggest that job-seekers should try hard to get even a glimpse of the environment of the workplace ... of whom they will be working with, and how autonomous (or not) they are expected to be. The viewpoint of any manager vs. that of any line-employee will be different because the roles are (entirely) different.