SS,
There is a fundamental difference in the way PPLs and ATCOs are trained to the point where they are let loose on their own.
At all times when ATCOs are under training, there is the instructor sat right next to them, on whose ATCO licence the trainee is operating. I can only speak for Heathrow, but this training period lasts for around a year before the trainee ATCO goes 'solo' and operates on his own licence. Obviously, units which are less complex and less busy will have shorter training periods. And trainees are only put forward for their validation board (SRG-run examination) when a pass in the said examination is as close to guaranteed as possible. The preparation for this would have included many ATC simulator exercises (at units where a sim exists of course) involving emergency after emergency, unusual situation after unusual situation, and many, many scenario discussions and theory questions. Very often the SRG-approved Unit Training Plan will entail familiarisation flights with based airlines, visits to agencies such as the Airfield Fire Service, Police, possibly flights in the local police helicopter etc etc.
I went solo in a 152 at EGNX after four hours.
Slightly different.