Yes but some of the best controllers do have an aviation background. I have found that no matter what your previous aviation speciality there will often be a time when that knowledge will assist a job well done. As for rocket scientists - I've trained a few in my time and have found that a considered well researched decision is often not the order for the day. What do you need to actually do the job - advanced kindy mathematics, common bloody sense and the ability to formulate and action a decision without delay. Unfortunately I suspect the selection is trick cyclist driven with the obvious inherent pear shaped results. Good luck it's a great job with some great and memorable people to work with along with enormous frustrations and the obligatory dikhead.